Corrupting Spores (DoD)

A small patch of three poison mushrooms magically sprout in a 5-foot square that you can see within range. The mushrooms emit toxic spores, and any creature that starts its turn within 10 feet of the mushroom patch must make a Constitution saving throw. On a failed save, the creature takes 1d8 poison damage for each mushroom in the patch and is poisoned until the start of its next turn.

Until the spell ends, you can use a bonus action on your turn to cause an additional mushroom to sprout within the patch

At Higher Levels. When you cast this spell using a spell slot of 5th level or higher, one additional mushroom sprouts with the initial patch for each slot level above 4th.