Acid Nimbus

As a bonus action, you conjure a grey cloud from which drips orange burning acid within range. The cloud appears and floats 10 feet above the ground and occupies a 5 foot cube. If there is no space for the cloud to appear then the spell fails. Every creature below that area must make a Dexterity saving throw or take 1d8 acid damage. On a successful save, the creature takes no damage. As a bonus action, you can move the cloud up to 30 feet in any direction horizontaly and additionally 10 feet up or down. 

At Higher Levels. When you cast this spell using a spell slot of 3rd level or higher, the damage increases by 1d8 for every slot above 2nd level.