sound3e, PhysicalOrchesta_POte (2) (Floral Vortex)
The Flooded Dungeon is a large area with a constant blue tint, and bright lightning strikes. It is a very large maze containing large, blue organisms that seem killed and splattered all over the floor. Chainsawing the organisms causes the flowers around them to flash in a wave pattern.
Doors scattered around the area lead to dark, foreboding hallways with metal bars and bright lightning flashes. In one of the hallways, there is a door that can be knocked upon with a doorbell next to it. Repeatedly pressing the doorbell will open the door, leading to a passage that will take you to an isolated area. In the isolated area is one of the organisms, and a wind-up key on the ground surrounded by barricades and a construction sign next to it. You can leave the isolated area by using the Fairy effect to squeeze under a creature blocking the exit.
There are a couple of ladders in the dungeon, one of which leads to a hallway with a door to FC Caverns. However if you fell from the Wooden Polycube Ruins, there will be a small flower on the ground next to where you landed.
One of the hallways leads to a brightly-lit open door, and beyond is near-total darkness. However, if you travel north for a bit and then move back south, the area will gradually grow brighter, revealing a strange and colorful underwater garden surrounding a deep blue vortex. Interacting with the center of the vortex will teleport you to the similar vortex in Cotton Candy Haven. In the northwest part of the garden is a giant eye, and moving behind it will take you back to the main part of the Flooded Dungeon.