Balloon

You create an opaque pressurized balloon of force at an unoccupied point that you can see within range. The balloon lasts for the spell's duration, expanding until it pops.

The balloon is an object with one hit point and AC equal to your spell save DC. It is immune to Bludgeoning damage. If the balloon drops to 0 hit points, it pops and the spell ends.

When you cast the spell and as a bonus action on your subsequent turns, you may inflate the balloon, increasing its radius by 5ft. The balloon expands around any obstacles as possible, and pushes any creature smaller than the balloon's new radius out of its new area. Any of those creatures may use their reaction to make a Strength saving throw, popping the balloon on a successful save. After the balloon inflates, roll a d10. The balloon pops on any result for this roll less than or equal to the balloon's radius divided by 5.

When the balloon pops, it deals 2d6 Thunder damage, plus 1d8 Thunder damage for each 5ft in its radius, to each creature within 5ft of it.

If you lose concentration, dismiss the spell, or leave the range, the balloon does not pop but harmlessly shrinks to nothing with a fart sound.