Mime

From The Sims Wiki, a database for The Sims series that anyone can edit

The Mime is an NPC in the The Sims expansion, House Party. Whenever you throw a bad party, the mime will come and, like the Tragic Clown, try to make the guests happier but end up making things worse instead. You can slap him but this has little effect. The only way to get rid of him is to make everyone happier, end the party, or delete him using the move_objects cheat.