Sheak, a sentient slime

The very fat and lumpy man standing before you is revealed not to be a man at all by the light of your bedroom's lamp. The creature sheds its cheap cloak and reveals its jiggling translucent green body. It is roughly in the shape of a hunched man, but as it is exposed it slides into a shape more like a mound of pudding. A slime! You take a step away, aware of the insatiable sexual hunger of such creatures and how they often make a meal of their lovers.

"Wait!" the voice commands and you freeze, though mostly out of surprise.

Within the jiggling green body you see a brain contained in a reddish bubble of fluid. This is not a normal structure within a slime.

"I am not a simple slime," the creature protests in a voice that sounds like gurgling water. "I am a wizard cursed to this form. My enemy has made me this way and I have no escape. Please, I mean you no harm. I have used all of my illusion powers to get this far, but I have no more magic."

"You're a...monster," you whisper.

"I am," the slime says sadly. "My name is Sheak. Though I can think and control myself I still have the urges of a slime. Even now it is almost impossible to stop myself from attacking you. Please. Trust me and I swear no harm will come to you. I need pleasure, I hunger...please..."

The pitiful wobbling pile of sludge spills onto the bed and covers part of the floor. You can see creeping tendrils of slime extending towards you, but remaining at a distance.