It's a fantasy role-playing game.

DM: You are Caleb Widogast, a human wizard . You are the member of the famous group of adventurers. Previously, The others try to persuade Nott to join them in swimming down, and you casts Suggestion on her to convince her to try it. Nott, Beau, and Fjord join Yasha and Jester inside, Nott forgetting she's holding the weasel, who lives but isn't happy about it, joined shortly by you, Caduceus, and Nugget.
DM: The tunnel goes on for about another 60 or so feet beyond that grate, before the tunnel opens up into a square-like chamber with a singular pillar that marks the center of it. It's still one foot of water all throughout this entire area. Once you go past this-- You can look past where this pillar is, the chamber seems to close off and another tunnel continues on, almost like this is just a waypoint chamber. On the right side, you see a much smaller grate: maybe a foot and a half, two feet across, with a more dense cross-lattice of bars.
Player: Not able for Frumpkin to squeeze through that, I'm guessing.
DM: Frumpkin's size? How big of an octopus is Frumpkin? An octopus, I'd say it would be about that big.
Player: I'm imagining I am not summoning a gigantic octopus.
DM: But octopuses can squeeze through some pretty small spaces. Yeah, so I'd say make an athletics check for tiny octopus Frumpkin.
Player: And that would be strength-based, yeah? Because it doesn't say on his thing. That is a nine.
DM: Frumpkin gets partially through but the nature of the lattice and Frumpkin's unfamiliarity with the octopus form reaches a point where it can't quite get all the way through.
Player: That's true! It's only his second time. Okay buddy, forget that. Back it up. Is there anything unique about the pillar down here or is it just basic stonework?
DM: Looks like basic stonework, it has a slight curvature to it but it's probably placed in here either as a load bearing piece since this is beneath a heavier city or-- It doesn't look remarkable or have any other purpose beyond just being a support pillar.
Player: Are Frumpkin and I able to tell if this goes water all the way to the ceiling of this chamber or is it water with air above? Or it's all water?
DM: The water only goes up to a foot, and then it's air for the rest of it. It's about ten or so feet tall, the chamber.
Player: Okay. Is there anything out of the ordinary if he pokes his head up out of the water?
DM: Make a perception check?
