When the Skool takes a field trip to the beach, Team Save Earth's attempt to have a carefree day is interrupted by an encounter with a monstrous creature.
- Batman Gambit: Dib uses reverse psychology to get Zim to help his plan of fighting the sea hydra, by condescendingly suggesting that Zim couldn't help anyway. Naturally, Zim is insulted enough that he goes all in on the plan.
- Beach Episode: This chapter's plot is driven by the skool sending everyone to the beach on a mandatory field trip. This results in Dib, Zim, and Tak's groups having to team up to fight a demon sea hydra.
- Continuity Nod:
- The freak storm created at the climax of the previous chapter creates an upswing of good weather, creating the opening for the beach trip here.
- When hearing about the field trip, Zim assumes it's to another botanical garden, like back in Episode 11.
- Crazy-Prepared: Dib and Steve take a lot of equipment with them on what's supposed to be a simple beach trip, but it all comes in handy.
- Destination Defenestration: Tak forces Sara to do this to herself after Sara makes fun of her attempted excuse to get out of the field trip.
- Didn't Think This Through: It's only after attacking the hydra that Zim realizes he doesn't know how to restrain it.
- Enemy Mine: Team Save Earth and both Irken factions reluctantly work together to fight the sea hydra.
- Harbinger of Impending Doom: Squidman, who first appears as a crazed beach hermit warning everyone about the sea monster.
- Kaiju: The demon sea hydra.
- Logical Weakness: Dib figures out how to beat the hydra by telling everyone to blast as many of its heads off as possible. The hydra grows all its heads back and extra ones until it has dozens of heads, and almost immediately afterwards collapses on its own. It had too many heads at once and not enough blood for all of them, so it lost consciousness without oxygen properly getting to its brains.
- Ninja Pirate Zombie Robot: As if having a hydra that lives in the ocean wasn't enough, it also turns out to be a demon. Lampshaded by Dib, who notes this is ridiculous even by his standards.
- No-Sell: The sea hydra isn't affected by any wounds short of decapitation, which just gives it more heads, anyway.
- Our Hydras Are Different: The sea hydra starts out looking like "just" a sea serpent, before its true nature is exposed as it starts regenerating heads. Then, when they try using the "cauterize the stump" trick, the fire causes it to mutate into a demonic form.
- Shout-Out:
- When they first see the sea hydra, Steve comments that "we're going to need a bigger net".
- The way the hydra is defeated is taken straight out of The Order of the Stick.
- Unexplained Recovery: Zim is shocked to see Squidman alive when he saw him apparently die in canon, and doesn't get a proper explanation for his survival.
