I have the power of anti-matter!, an elements related powah 
I would give myself only the power of matter, so the antimatter will explode.
anti-matter is the existence of negative matter, why would it explode upon the existence of matter? it doesn't make sense >.>
It's a comic book thing...
I'd been meaning to join this anyway, so here goes.
I am made out of organic diamond! So...yeah, I assume that counts as a power, a moderate form of invulnerability. My item is...a Green Lantern Ring!

If the first doesn't count as a power, my character's power is the same that he would get from a GL ring, it just comes from him naturally...