Blissful Ignorance. Meanders back and forth until disturbed, and ignores anything is doesn't see as an enemy. Once an enemy comes within range (30) the Volatile Mosskin walks towards it.

Infecting Burst. The Volatile Mosskin Bursts, causing every thing within 5 feet of it to make a DC 15 Dexterity saving throw. On pass, the target takes no damage. On fail, the target then must make a DC 15 Constitution saving throw. On fail, targets take 3d12 +6 infestation damage, and an additional 1d8 infestation damage the following turn. On a pass target takes half damage, without any the following turn.