Decayling - OC

Part of a minigame I am working on
Lore-
The Decayling is a mutation of a man who usually ravaged cities with gas related substances. One day, he found himself in a safe place for him to stay so he will not be caught by the police, he saw the room go dark. Which was strange since there were several open windows. He ran to one of the windows, but there was just a fleshy substance blocking it. He turned around and saw a human skull covered by the fleshy substance. The skull was being held by a long tendril connecting to one of the blocked windows. "Hello my child," The skull said, "your life seems to be in quite a predicament. Would you like to be given a greater purpose?" The criminal agreed.

The hivemind, (which is what he had just negotiated with) told him to cut his cheek with a knife. So he did. The mother hivemind then reached out a fleshy limb and inserted a mutation into his bloodstream. He is the only monster who has free will. His objective is to attack the lab containing the other mutations.
Mechanics-
Can spit 5 poison clouds, has a lot of health, and is slightly faster than a human.