Grease
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.
Grease 5e 2024 vs. 2014 edition differences
The 2024 version adds "Nonflammable" and allows Sorcerers to cast it, whereas the 2014 version does not specify flammability and is limited to Wizards. The 2024 version states "have the Prone condition," while the 2014 version states "fall prone," but both mean the same effect.