Create Slime

You summon a spray of caustic sludge that splatters a 5-foot square within range. Each creature in that area takes 4d4 acid damage and each turn thereafter, a creature takes 3d4 acid damage when it enters the spell's area for the first time on a turn or starts its turn there. Additionally, the area becomes difficult terrain and each creature that ends it's turn must make a Dexterity saving throw or have it's speed reduced to 0. At the end of each of its turns, the target can make a Dexterity saving throw, ending the effect on a success,

At Higher Levels. When you cast this spell using a spell slot of 3rd level or higher, the damage (both initial and later) increases by 1d4 for each slot level above 2nd. Additionally, the area increases by 5 feet on each side.