Tome Bearers Trebuchet

You create a boulder and fling it at one creature within range. Make a ranged spell attack against the target. On a hit, the target takes 3d12 bludgeoning damage. Hit or miss, the boulder then explodes. The target and each creature within 10 feet of it must succeed on a Dexterity saving throw or take 6d6 bludgeoning damage.

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