Andavean's Force Bomb

You create an invisible bomb at a point you can see within range. As a reaction, you can detonate the bomb, causing it to explode in a 20-ft radius. All creatures in the spell’s area must make a Constitution saving throw. If the saving throw fails, a creature takes 8d8 force damage and is knocked prone. On a successful save, a creature takes half damage and is not knocked prone.

At Higher Levels. When you cast this spell using a spell slot of 6th level or higher, the spell’s radius increases by 10 feet for each slot level above 5th.