Diddy Party

Nonflammable grease covers the ground in a 10-foot square centered on a point within range and turns it into Difficult Terrain for the duration.

Your entire body is covered in oil. You gain advantage to being grappled, but your weapon slips from your hand. When the grease appears, each creature standing in its area must succeed on a Dexterity saving throw DC 15. A creature that enters the area or ends its turn there must also succeed on that save or fall Prone.