The Paris catacombs, in which Zolf, Sasha, and Hamid get crushed in a cave-in. Hamid and Sasha, unable to see in the pitch darkness, scramble to pull Zolf out, only to realize that Zolf has lost the use of his second leg (after Hamid accidently severs his Achilles tendon while trying to dig him out), Hamid's hand is not working, and they cannot find their way out of the tunnels. As Sasha goes to look for a way out, she is stalked by an unseen monster with unnatural screams. The party desperately struggle towards what they think is an exit, crossing a bridge over a ravine, only for tentacles to pull Zolf and Hamid one by one into darkness as Hamid shouts for Sasha to save herself.
The rest of the episode contains a much-needed content warning for body horror: Zolf awakens in a tube with a pipe in his mouth and discovers he has no legs and pipes emerging from one arm. He then sees an unconscious Sasha whose organs are suspended outside of her body.
It is also implied that a similar process would happen to Hamid should they not have woken up then, as the scar on his arm is open and several medical tools were left nearby.
Everything about Mr Ceiling: an AI made of hundreds of human brains (many of which are from children) that controls the world's economy but can't understand morality, and frequently alters people's memories to prevent them from telling the rest of the world about him, to the point that his own creator is simply a mindless husk? Yeah.
Season 2
The airships, though equipped with safety guidelines that clip passengers to the ship, do not stop people from being thrown off the ship and then left dangling until someone comes to pull them up.
Season 3
The tunnels under the Rachet factory in Damascus, which are filled with horrifying traps at every turn. Particularly notable is the "coffin trap," which seals its victim in a heavy metal coffin that sinks into water and can't be opened from the inside. Even more horrifying? Sasha only just made her check to notice it.
Season 4
In Hamid's sequence where he sees "Aziza" in the theater, he appears to be surrounded by people in the seats. Upon closer inspection, they are merely life-sized mannequins.
