So finally here we are, sorry for being late but we had a lot to do and it's mostly Kashtan's fault for convincing me to change everything from fighter to monk.
I have not attached ability score numbers, I'll let Joy decide what's feasible but I'd like to go with my abysmal 12 12 11 9 9 8 roll if possible.

The 2nd sheet with special traits is just a suggestion, modify as you see fit. I guess phagocytosis / chemosynthesis could work like a mentally illmutation spell, just way slower. the point is that while I may digest or synthesize everything, it's painfully slow because its chemistry obeying laws of nature, conservation of mass and energy not magic. So it's only practical to build or digest really small stuff unless you give me a week or so. Ki is a bit esoteric but would count as the plasmoid body's ability. I need the healing abilities later on because the living metal cannot be healed by others. So yeah, I can do a lot but also have a lot of drawbacks and penalties, that's the fun.

Let me know what you think, i believe monk fits me best because i can go unarmed and unarmored. My body serves as weapon and shield and I don't like carrying anything.

Again I don't mind if I'm borderline useless in the beginning, that's the joke.

That said, I'm fine with everything poor Joy can manage. You're the DM. Just make sure it doesn't get overly complex to the point of being unplayable.