Creature Features

In the spirit of my ruminations on producing things that don't quite fit clearly in a single creature/object/trap category, I bring you Creature Features. Much like the venerable Green Slime, these oddities are living and yet act more like objects in some ways. These weird denizens of the dungeon are trap-like in their ability to be hazardous to explorers, yet they are alive. Place them in your megadungeon with glee.