GR1M_1S_G0N3_

From what I understand, his power is about density, and i can list quite a few examples; in the comic he breaks Coupes knives  by toughening the parts she was try to stab, it looks like he increased the density in his shoulder to push the glass out and then close the wound, by increasing the amount of density in his limbs makes him hit harder/jump farther (him pinball-ing himself in episode 8), and his response when hes asked who threw him through the door.

Yes, he does also have pain immunity, which would be a correct physiologic response for packing muscle fibers impossibly close together -- there is not much room for axon channels or nerve endings for sensory input, but saying as he can still move around and his heart still beats, id say most if not all of his movements are based almost solely on motor functions/actions rather than sensory based inputs. which i don't think would be a far fetched idea saying as he doesn't just have a pain immunity, but that he quite literally did not feel the glass shard whatsoever and only became aware of it when Melavola told him. there are actually people that don't have/have enough sensory input channels, and if it weren't for the fact that he is not only strong and durable, but can increase mass to deflect blows, he wouldn't be dead because of a fight, he'd likely bleed out from a minor injury because he wouldn't know he was injured.

Also! more physiology/disorders for ya! (iamcompletlynormalaboutthis)

he does have ANOTHER bonus that isn't a superpower, but is definitely the reason he can BE a superhero/villain; the fact that he was not born with his powers. this gave him enough time to grow and develop his para/sympathetic nervous system to that he could learn what hurts, how it hurts, and what it means. if he was born with the density/pain immunity, he might have actually had poor motor function or developmental delays. the closest real-life counter to this idea is Congenital Sensory Neuropathy with Anhidrosis (or CSNA), and babies/kids born with it often have self-mutilative tendencies (biting fingers/tongue off, intentionally burning themselves),no sense of temperature regulation, poor emotional regulation/mental disabilities (because the condition is neurological), and often run fevers so hot they experience seizures .

it is the difference between being on fire and:

--aware and in pain, trying to put it out imminently