Unlocking a treasure chest, only to find another treasure chest inside it. It appears Edmund likes to toy with expectations.
Or unlocking a treasure chest, finding another treasure chest in it, and then finding another treasure chest in that.
Not as funny when they're gold chests, as you end up wasting two or three keys, or might not even be able to open all of them (unless you're holding the paper clip trinket).
Even better, beating Mega Satan with this power up. Enjoy killing Mega Satan by peeing onto his face! Doubles as a Crowning Moment of Awesome, obviously.
Isaac can wear his mother's brassiere or her menstrual pad as items. Doing so causes the enemies to freeze or back away, respectively. Presumably, they're Squicked out by the sight of it!
Segmented enemies like Larry Jr. will even fall apart when they try to flee. They are so disgusted that it breaks the laws of physics.
When you meet Greed in a hidden room, you can immediately leave through the hole you made without having to defeat him. Hi, Greed. Bye, Greed. If you have X-ray glasses, you can even use his room as a shortcut, running past him without ever engaging him.
Greed got wise to this, and, as such, it no longer works in Rebirth: the entrances to the rooms around the hidden room get blocked until you defeat him.
The beggar that runs the shell game in the arcade is a jerk. Giving you a giant grin as he takes all your money without giving you the items you want? Seeing the slot machine throw a troll bomb at him is just too hilarious a karma to be true.
Similarly, sometimes the Beggar "rewards" you with a troll bomb. His eagerness to kill himself makes whatever money you wasted on him worth it.
In Wrath of the Lamb, getting the Speed Ball item (a syringe with white fluid in it) gives Isaac very large, dilated eyes and a little smile. It looks incredibly goofy (though less so once you see the bloody syringe◊ sticking out the back of his head).
The glitches in this game can sometimes cause hilarious reactions from players. Especially since, given the tone of the game and previous games by Edmund McMillen, it's difficult to tell if some of them are actually glitches.
One of the random effects of pills is "I Found Pills" with the description "...and ate them." This pill also causes Isaac to get a silly, derped look on his face and make a faint "duuur" noise when you take it.
Even funnier is the Horse Pill version of "I Found Pills": When Isaac takes it, he gets a face that seems to look like he's doing an exaggerated impression of an actual horse (this is the current page image). If the face wasn't funny enough, the voice clip for this pill has the narrator shouting in a hammy voice, "I FOUND PILLS!"
Another effect of the pills is the "Puberty" pill, which causes Isaac to grow a few scraggly hairs on the top of his head. Then you realize, those are pubes growing on his head...
Taking three Puberty pills gives the "adult" transformation, which is just a free health-up... but also gives Isaac some scraggly facial hair and deeper voice clips. This applies on all characters, including female ones.
Even more amusing pills in the remake. A new pill effect is "R U A Wizard?" This causes Isaac to get a derpy, walleyed look that forces him to shoot his tears diagonally for a short while. The Wiz, a Dunce Cap, has a similar effect, complete with the same walleyed expression.
The fact that the game treats this as a positive pill effect makes it even funnier.
Any of the secret messages from the Fortune Telling machine. Some of these include cryptic nonsense like "LOOK TO LA LUNA" or "DON'T LEAVE THE HOUSE TODAY". Then there are some that seem to be talking to the player, such as "GO OUTSIDE" or "YOU ARE THROWING YOUR LIFE AWAY". The way the game is just totally fucking with you in this moment is priceless. Oh, the best of all these? "YOU ARE WORSHIPPING A SUN GOD."
Rebirth continues these messages with blatant insults like "YOU WERE BORN WRONG", or "REBIRTHGOT CANCELED".
Some of the boss enemies make some pretty funny expressions, such as Chub's poker face during her intro, War's Oh, Crap! face when he runs out of stamina, Pin's stereotypical frown (it looks exactly like ":c"), or even Loki's expressions of pure glee while he fires his 4-way shots.
The fact that of all the Seven Deadly Sins, the only one without a unique sprite is Sloth. Or, in more modern terms, laziness.
As another rung to how goofy Sloth is, Edmund would later confirm that the Bob items and transformation are in fact referring to Sloth by his first name. In addition, this mean that Sloth finally gets a unique sprite set due to the Bob transformation... and then he can't be bothered to use it. And on the final rung of these recurring bits of lore, Edmund has also stated that Sloth represents the brother of Isaac's father... Meaning that logically, Bob's your uncle.
One of the between-level dreams features Isaac using the toilet... and discovering there's no toilet paper left. His reaction is the typical "No!" reaction used in other dreams, but it seems more like he's going "Curses!" this time around. Don't worry, Isaac, other people can relate.
In Afterbirth, one of the new dream transitions is Isaac and his penis falling off. His reaction is what any man's reaction would be if his dick fell off.
Repentance adds a dream where Isaac goes cloud watching. Then he realizes one of the clouds is flipping him off.
Fighting Wrath, a mini-boss who uses bombs... while you have the Remote Detonator on hand. Even better if you have Bobby-Bomb on hand, which pretty much means you can sit back and laugh while Wrath gets chased by his own bombs.
In Rebirth, picking up the Rosary item allows you to potentially sell your soul for the Bible.
Rebirth adds an item called "How to Jump", its description being "it's time you learned." The animation for jumping is just Isaac's head slapped onto the hopper sprite. It's as ridiculous as it sounds; it must be seen for oneself.
One secret seed you can input, BASE MENT, gives you a seemingly normal run. Basement I and Basement II are normal, but instead of moving on to Caves I, you go down to Basement III?, which is exactly like Basement I. And then Basement IV?! and Basement V...And then Basement VI and Basement VII. If you have time, you can play the seed for 4 hours!
If you make it all the way to the thousandth floor, you'll get a special message:
The red poop dropped by the Carrion Queen will damage any other enemy that touches it. Because of this, during the Boss Rush, it's possible for some bosses to die as soon as they enter the room.
Cancer, in real life, is a horrible, life-threatening disease. Cancer in The Binding of Isaac is probably one of the best trinkets in the game, since it significantly increases your tear-firing rate, even if you've already hit the cap. The tagline description for it in Rebirth is even "Yay, cancer!"
Made even better by the fact that you can get rid of it at any time!
One way to read Envy having the same attack method as Fistula and Teratoma is that it's a Stealth Insult. The joke being, of course, that the dedicated troll amongst the seven sins is functionally identical to a tumor.
One ending (ending 11 in Rebirth) has Isaac trying to open up the chest, only for It Lives! to appear, try to growl intimidatingly, and give an incredibly cheeky grin.
The very next ending (actually the previous ending in Rebirth) has ??? give Issac a cheeky grin as well. Made even funnier in the original game/WotL, where the Dramatic Chipmunk Sting plays during this scene.
The Greed Mode ending continues this gag. We find out Greed is yet another posthumous Isaac as he gives us this big dumb grin.
Afterbirth+ has the Greedier Mode ending following the above with his head falling off and a literal geyser of spiders erupting from the severed neck. Because why not.
He's the number one. God's favorite son. His flowing robes reach down from heaven. His hands will touch you! Build a world around you! The light within his heart is enough to heal us all! He will fill your soul when life takes its toll. Your only goal is to find his kingdom. His love is real! The golden seal! Trust in the book and the bread you took!
Dear Diary is even better, which has Isaac rapping about his plight in the most twistedly funny way imaginable.
"Once I though I had it good, probably Mom misunderstood, when God came down from heaven, and turned the shit up to eleven."
In order to accommodate Nintendo's policies, Rebirth will be somewhat censored, including a fig leaf to cover nakedness◊ and God being replaced with a dog.◊ The censoring is an April Fool's joke, but the game did release on the Wii U and the New 3DS.
And under the main post, there's a bunch of strikethrough text that details the many other changes that will be made.
Note: other minor changes made to the 3ds and wiiU release are as follows: isaacs blood has been replaced with sweat. all instances of pills have been replaced with lollipops. all demon forms are now purple instead of black. you can now choose the gender identity of eden when you choose to play as them. maggy is now Hispanic. the womb has been replaced with a meat boy themed world. all instances of suicide now have text popups of local suicide hotlines. the letters R P A and E have been removed from the games code. isaacs mother is no longer overweight unless you choose the fat acceptance mode from the options menu, you can also replace mom with isaacs dad or isaacs dog from this menu. all references to isaacs sexuality being anything other than straight have been removed and he now carries a football. isaac is no longer shamed for dressing slutty. mulligans now wear police hats. any instance of abortion has been replaced with a funny cat video. the devil is no longer black. Isaac no longer eats dog food and spoiled milk, but healthy snacks of apples. the A button has been replaced with the “Trigger Button” a simple tap when triggered will close the game and removed it from your system. Isaac is now 18. racism no longer exists and finally all instances of my name have been removed from the game as well as any association with my blog, past games and this post.
The Adversary's design. For the record, The Adversary is the post-mortem version of the Dark One, and all of the other undead bosses have suffered some form of Body Horror (Monstro II is missing most of his skin, the Carrion Queen is almost completely skeletal, etc). The Adversary? Covered in bandages and missing a horn. It almost looks comical.
When the achievements for Afterbirth were posted on Steam slightly before release, those with Real Platinum God saw that they no longer had 100% of achievements. Instead, they had 69%. Whether or not this is intentional is unknown, but likely.
Edmund asked Twitter what the antithesis of "Immaculate Conception" would be. The results... well, just read for yourself.
Two of the pills from Afterbirth, named "One Makes You Larger" and "One Makes You Small", make you bigger and smaller, respectively. They also stack, so you can either end up with an Isaac who can barely even be seen he's so small, or an Isaac who takes up half of the screen with his size.
Ultra Greed's rotating sprites include several of his butt. This has reached the point of Memetic Mutation and causes things like this to pop up.
The Chaos item from Afterbirth. After picking this item up, all further collectible items in the run will be drawn from random item pools, which can have... interesting effects. Such as an Angel showing up and offering you Butter Bean or a Devil Room offering the Halo. And then there's the expression◊ Isaac gets after picking up the item...
Upon finding Bum Friend, Dark Bum, and Key Bum in one run, a cutscene will trigger, showing the three merging together to become Super Bum.
The Epilogue that plays after beating Mom for the first time starts off with her about to kill Isaac... then a Bible hits her on the head.
The Aprils Fool challenge in Afterbirth+. Nothing is what it looks like, every boss is the Bloat unless you randomly use Book of Revelations (every active item is Dead Sea Scrolls on steroids, so have fun if you get an infinite-use item like Guppy's Paw), and the reward is Maggy starting with a pill.
To make this even funnier, a Reddit user once suggested a challenge where every boss is The Bloat. When Afterbirth+ came out (and with it the Aprils Fool challenge), they were banned from /r/FUCKBLOAT (the official anti-Bloat subreddit) and forced to use a unique "I Love The Bloat" flair on the main Isaac subreddit.
The icon for the 1000000% achievement? A glittering stop sign with a gold background. The message? "Just Stop!" The kicker? It's not even the highest completion percentage you can achieve.
Delirium can shapeshift into other bosses, and if it rolls a boss with multiple health-based forms, its form will adapt to its current health. This means that if Delirium transforms into Brownie at low health, it kills itself as the aforementioned boss splits into Dank Squirts when its health gets low, resulting in a hilarious anti-climax.
While this was eventually patched out, there's another way to make a fool out of Delirium. Have Vade Retro, whittle it down to 50% HP, wait for it to transform into a ghost boss (Haunt, Forsaken, Rainmaker, Heretic, etc.), and use the item. Cut to death animation.
Sometimes, if you get particularly good items during a run (especially in the early floors), bosses go from mildly difficult to a complete joke. In fact, it's not uncommon for the following scenario to take place: the Versus Character Splash appears, showing the boss looking menacing compared to your crying character... and almost immediately after the fight begins, the boss reduced to a big red splat mark on the floor once you let'er rip. The Anti-Climax potential can easily elicit a few chuckles, especially if it's one of the harder endgame bosses, which crosses over into Awesome.
It's extra funny if one of your items is Ipecac or Number One. You literally vomit/pee on them to death!
On another note, due to the way synergies work, your tears change shape, color, and size. Brimstone results in a good-sized blood beam fired from the mouth, as an example... but you get Number One, it turns yellow. Yes, your character goes from firing blood lasers to firing a SUPER LAZER PISS. From the mouth, too.
An addition made in Repentance is Horse Pills — larger pills that grant exaggerated versions of the typical effects; good becomes great, bad becomes worse, and the narrator is more hammy. This is applied to almost every pill in the game... including the already funny "I Found Pills", which causes Isaac's face to morph into a horse's grin while the narrator screams "I FOUND PILLS!" at the top of his lungs. This hammy narrator can also lead to lines like "EXPLOSIVE DIARRHEA!" and "QUESTIONY QUESTIONY QUESTIONY!"
During the second phase of the Dogma battle, there are preachers in the background rambling and ranting verses of the Bible and the way they say their lines in such an over the top way that you can't help but laugh even in spite of Dogma being a Knight of Cerebus.
BLASPHEMY AGAINST THE HOLY SPIIIIRIIIIIIIIT!
What do you get when you cross Loki and Hornfel and someone insane enough to stich them together? You get the Horny Boys, one of the funniest bosses made for Isaac yet.
Hornfel has always had a problem with getting motion sick when he goes too fast… so when Loki starts posing faster and faster to fire off larger volleys, it ends predictably. The tell for this attack even has Hornfel realize exactly where the attack is going before Loki starts.
Also the fact that they only appear in Gehenna, of all places. You fight your way through a bloodstained Satanic temple filled with depraved cultists, only to come across one of the silliest bosses in the game.
The Reverse arcana Tarot Cards are an interesting lot, having effects that are either the opposite of the original card, or behave in the spirit of that opposite. Death Reversed turns two enemies in the room into charmed skeletons instead of acting like a Smart Bomb, Temperance Reversed causes Isaac to eat five random pills instead of spawning a Blood Donation Machine, etc. But Tower Reversed has among the most outlandish interpretations of this; instead of dropping several bombs into the room and destroying most rocks and pots in it, the card causes reverse explosions that will create rocks and pots in a way that leaves the exits unobstructed.
Reversed High Priestess also deserves a mention. When you pick it up, the description is a brief "Run.". Cue Isaac being barraged by an onslaught of Mom stomps for a solid minute.
Reversed Emperor sends you to a boss fight 2 floors after. If used in the ??? floor, it will spawn MONSTRO instead, and you get Hush's completition marks by beatingMonstro, who at this point in the run should be a Zero-Effort Boss.
In the event that 700+ items isn't enough variety for the player, Repentance introduces "Glitch Items" that are found from TMTRAINER or have a chance to be in Secret and ERROR Rooms after beating Delirium with Tainted Eden. They can do anything, to the point of some downright absurd effects, such as replacing fireplaces with End Chests and allowing the run to be ended in 3 seconds. The DELETE THIS challenge has the player start the run with TMTRAINER and go all the way to ???, ensuring a chaotic run.
Even the "item get" sounds for glitch items are completely randomized, including its pitch, which can result in anything from Satan's voice clips in a high pitch to even a slow-mo version of Mom andDad arguing
The trailer for Repentance is basically Awesome all the way, but in one instance, as it flaunts the game having MORE ENEMIES, MORE ITEMS, MORE ROOMS, MORE ACHIEVEMENTS, it suddenly drops MORE POOP! Given that this update added Dross, Giant Poop, Charming Poop, and Tainted ???, it certainly wasn't lying.
Suplex!, an active item gotten by defeating Delirium with Jacob and Esau, allows you to, well, suplex enemies. The hilarious part is when you realize there is no limit to it. Isaac (or any of the other characters) can give a Suplex Finisher to himself, his dead body, Satan, his mom, and himself as a fetus.
Taken up to eleven should Tainted Samson use Suplex during his Berserker Rage. He slams things into the ground so hard that they EXPLODE!
Tainted Jacob is based on the Biblical story of Jacob fleeing after taking Esau's birthright. So what happens when he gets the Birthright item? It summons anothershadowy Dark Esau; in other words, grabbing it just pissed Esau off even more.
Birthright Description: It's not yours.
Several of the new planetarium items embody puns based on what they do in relation to what sign they represent. These range from the painfully obvious to the hilariously subtle.
Terra: "Born to rock" turns Isaac into a Rock Monster and his tears into high damage boulders that can break things. The pun is so obvious it is guaranteed not to rock anyone's world view.
Uranus: "Ice Tears" turns Isaac into An Ice Person and his tears can freeze enemies into statues for an instant kill on regular enemies if a threshold is passed. While it's mainly a reference to Uranus being extremely cold (with an average surface temperature of -353 degrees Fahrenheit), it also paves the way for a hilarious (if not obvious) joke: Icy Uranus.
Jupiter: "You're a gas giant" makes Isaac hilariously obese and causes him to leave poisonous farts everywhere he walks. The planet Jupiter is a gas giant, so it turns Isaac into a different kind of gas giant.
Mars: "Double tap dash" turns Isaac into the boss War (based on the Biblical horseman). For some theological crossed wires, Mars is the god of war in Roman mythology.
On November 4th 2022, in order to promote a special G-Fuel flavor based on the game, a special daily challenge was made which gives Isaac a G-Fuel Item at the start of each floor. What does it do? Well, it gives Isaac an increasingly absurd combination of Base game items and First Person Shooter weapons, including Shotguns, Machine Guns, and even rocket launchers. No, not the Dr. Fetus + Rocket Jar synergy, an actual rocket launcher. Also, the more G-Fuels you get, the faster the gameplay becomes, the higher your speed stat becomes (even bypassing the normal 2.0 limit), and the more often everything explodes. Oh, and over time, as you pick up more G-Fuels, the narrator's voice grows progressively louder, until it gets to the point when the narrator just yells, "G-FUELLLLLLLLLL!" whenever you pick up a G-Fuel.
What's better? The fact that a G-Fuel Run can be played at any time using the seed: GFVE LLLL
Additionally, the challenge run in particular was set up that Baby Plum was one of the first bosses encountered. Defeat Baby Plum, and her defeat animation plays out as normal... until a CGI missile strike comes in and blows her to high heaven. Even funnier? After the challenge came and went, there's still a very small chance for that to happen.
Usually, The Gate is fought by itself along with its leapers. If it appears in the Boss Rush, it will chain its Brimstone through the other boss, as if it was another one of its lackeys. Since the other will most likely survive the attack, The Gate will attempt to chain through the target again. And again. It will not return to firing blood shots, not bringing in more leapers, just more beam until the other boss is reduced to nothing.
◊ is just priceless.
