Stonemelder

When the Stonemelder dies, it turns to stone and explodes in a burst of rock shards, becoming a smoking pile of rubble. Each creature within 10 feet of the exploding Stonemelder must make a DC 14 Dexterity saving throw, taking 11 (2d10) Bludgeoning damage on a failed save, or half as much damage on a successful one.

Melee Weapon Attack +5 to hit, reach 5 ft., one target. 5 (1d6 + 2) Bludgeoning damage. The Stonemelder can also expend a spell slot to deal extra damage, dealing 2d8 Bludgeoning damage for a 1st level slot, plus an additional 1d8 for each level of the slot above 1st.