Corvus' Big Black Mass

You conjure a large globule of foul, rotten, inky gunk at a point within range. The  big black mass jiggles like a bile balloon & floats for a split second before bursting in a horrendous explosion, releasing its disgusting contents on the unfortunate creatures and objects caught in the blast. Each creature in a 20-foot-radius sphere centered on that point must make a Dexterity saving throw. A target takes 6d6 necrotic damage on a failed save, or half as much damage on a successful one.

Creatures that fail their save have their speed reduced by 10 feet until the start of your next turn. Additionally, creatures within 5 feet of each other that fail their save are stuck together by the sticky black mass and can't move 5 feet away from each other until the start of your next turn. 

Creatures and objects caught in the blast are covered in foul, sticky goo and smell horrendous until they bathe with soap or until the end of a long rest, whichever comes first. 

At Higher Levels. When you cast this spell using a spell slot of 4th level or higher, the damage increases by 1d6 for each slot level above 3rd.

Corvus looked at the giants with contempt and grinned.  HIs eyes turned black and he pointed in the center of their group with his thin orange finger. "It's time for some nasty and blasty! Take a bite out of my BIG BLACK MASS!"