The Dank Depths is one of the environments in chapter 3 added in The Binding of Isaac: Afterbirth. The theme of the Dank Depths is tar and sewage. Rocks have a chance to be replaced with spikes.
Walks around the room, avoiding Isaac while spawning Attack Flies. Spawns a large number of flies upon death, which can be Flies, Attack Flies or Pooters.
Chases Isaac, dealing a full heart of contact damage. Upon taking enough damage, it collapses into a pile of goo, spawns a Spider, and leaves a puddle of slowing Black Creep. Will regenerate after a short time if not killed quickly. Leaves another puddle of Black Creep upon death.
Hops around the room, doing touch damage. Occasionally jumps high into the air, dropping down onto Isaac's position while firing 4 blood shots in the cardinal directions.
Randomly wanders around the room. Pauses to fire a Charger that deals one heart of damage when Isaac gets in its line of sight. The Charger is invulnerable, blocks Isaac's tears, has limited range, and flies back to the Chubber.
Fires a short-ranged spray of shots that leave behind slowing Black Creep. Occasionally burrows underground and reappears under any pools of black creep in the room. If Isaac stands on the Creep, the Tar Boy can fire shots straight upwards out of the Creep underneath Isaac.