Grease

Slick grease covers the ground in a 10-foot square centered on a point within range and turns it into difficult terrain for the duration. When the grease appears, each creature standing in its area must succeed on a Dexterity saving throw or fall prone. A creature that enters the area or ends its turn there must also succeed on a Dexterity saving throw or fall prone.

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. When the grease appears, each creature standing in its area must succeed on a Dexterity saving throw or have the Prone condition. A creature that enters the area or ends its turn there must also succeed on that save or fall Prone.