This is an escape

Marius is canonically like 5'5". Short king 💪

I think he has a full, humanoid skeleton underneath all the fungus. Sometimes bits of it are exposed.

Most of him is a sort of flesh-fungus blend, with the actual fungal growths and mold colonies mostly being on the surface, acting as skin.

Some of his hair is just hair, some is delicate mold that looks like hair, and some is just a spongy solid mass in the vague shape of hair. You can't tell the difference for sure until you touch it and feel the texture

It's canon that Marius sometimes doesn't realize that he's holding/playing a violin. I think this is because different mold colonies on his body sometimes develop a bit more independence and his body sort of does things without checking in with his brain. He can override them if he tries, but half the time he's just not paying enough attention.

This also explains how he "accidentally" grew a beard all of the sudden one day, then told Jonny that he had been "holding it in" and only failed to repress the beard growth because Jonny "distracted him" (also a canon account lmao)

The visible appearance of the mold shifts and changes continually over time as colonies grow, die, evolve, and are replaced

Marius never gets sick because any germ that touches him is either killed, consumed, or becomes part of the mold family 🤝

The mechs don't need a doctor for injuries, since they regenerate and can't be killed. However they can still get sick from time to time, so Marius is the self-appointed designated caretaker when any of them are under the weather

This man has so many textures. He is a sensory nightmare and a sensory dream wrapped into one. He is rough, he is scratchy, he is soft, he is spongey, he is gooey, he is fuzzy, he is silky, he is velvety, he is porous, he is hairy, he is smooth, he is rubbery, he is-