[@Mintz] your CS is interesting and I can tell you've put some thought into it. That being said, I think the power will need to be nerfed. Just a few things I noticed:

1) Peter lacks muscle, but he also has incredibly strong adhesive properties that can even beat people with super strength and can nullify most forms of harm, which seems to negate that weakness. 
2) If the slime can reject/nullify most offense against it, how does one win against him?
3) If the slime can dissolve most things, it makes any physical weaponry effectively useless.

I don't know how much of the IC you've read so far, but something I've tried keeping consistent are that these are rookies who are facing real stakes. I won't spoil too much, but right now they're in the hospital after their first battle. If Peter can just regenerate himself fairly easily, a lot of the tension is effectively gone.

What I think could make sense is Peter being able to turn his arms and legs into slime and manipulating them, but not the rest of his body. That way Peter still has a variety of techniques he can use and it keeps the substance of the slime power in tact, but it brings the "power level" down to a more manageable level and there are real stakes for the man every time he fights. I think the adhesion is fine too if it's a little more grounded, so to speak; for example, he could stretch his slime to the ceiling to swing from it like Tarzan, but he can't envelope a super strength villain with it. Maybe he can harden the slime to the density of a normal human body so he can do stretchy punches with it too. I'd say the slime would have to have some vulnerability as well; something like if one bullet goes through it, it's fine, but if a slime arm gets sliced by a sword, it's gonna detach from Peter's body.

Does that make sense? I tried keeping everything organized but I feel like I rambled a bit there. What are your thoughts?

That all being said, the character's background and biography are great and I think the slacker dynamic would be an interesting fit with the team. It could be explained that Peter was really high the night everyone else fought Thundercloud, and so missed the battle :P