After a lot of gameplay testing we have decided to go with three stages of mutation.
First stage is a fresh test subject. These chibi sized humanoids are plain and simple. When they pickup special mutagens they become a full fledged mutant. After eating X number of regular mutagens, they become juggernaut mutants for short period of time. The juggernaut's appearance reflect which special mutagens the player have eaten most of.
We would like the juggernaut's appearance to be a mix off all the mutations you have eaten, and in time we might implement this, but for now, for the proof of concept, this will do.