I used a random dungeon name generator and one of the suggestions it gave was "Death Talon Lair".
The dungeon itself was next to a swamp, so I thought that Death Talon could be a Black Dragon.
I asked myself, what sort of creatures would co-exist with a Black Dragon? Well, the dragon is immune to its own breath weapon which in this case is acid. Oozes and slimes attack with acid, so I thought maybe a Black Dragon would lair alongside them, using them as a natural defence.
Here's the map:
And here's the PDF of the stocked dungeon: Death Talon Lair