Damp Caverns

Spawns
Mushrum

Black Imp

Spitter

Lemurian

Bosses
Magma Worm

Ancient Wisp

Artifact
The artifact gate can be found in the upper-right of the map, in one variant. Along the right edge of the top most platform there will be the artifact gate, with a short vine leading down to it. The artifact will not be present, however to the right, just off screen and only reachable with a photon jetpack (or 7? rusty jetpacks) are some smaller ledges. Reaching those and then 'dying' by going off the top edge of the screen will respawn you above the artifact gate, now with the Distortion artifact.