You are granted a random superpower, how would you defeat the poster before you?

I got Destiny Manipulation: you may be immune to my power, but all over the world there are susceptible guys just now serendipitously realizing how they should work together to bring you down – sure as I’ve cheerfully authored several eye-rollingly self-indulgent God Mode Gary Stu plot twists for yours truly.

Of course you’re not match for my powers of physical restoration. That priceless Ming vase I just smashed over your head? I just restored it to pristine condition so I can smash it over your head again.

http://powerlisting.wikia.com/wiki/Power_Reversal

Looks like the shattered pieces of that Ming vase will remain shattered pieces, eh? In fact, everything you’ve touched has shattered into pieces, including your skull.

But your use of your power spread further than you expected, and interacted with my power:

Breaking the sealed form apart and restoring me to my original power which was (okay, so I’m choosing another one because I got to hit you with something):

So yeah, apparently I’m all about the abstractions of power, which is no wonder why I had my original form sealed off. So seeing as how I define my very own existence, I’ve decided that buddha_david just doesn’t fit into the quantum makeup of my universe, and in a puff of non-logic disappears.

enchanting myself with invisibility, i find Hoopy Frood fast asleep with a huge contented smile on his face despite having been in hibernation for 10 000 years. silently i enchant a shard of his old seal and re-imprison him in stasis, locked in a happy dream.

I cut you. You are cut and sliced. Sliced and cut 'till you are dead.

i enchant myself with nothing, and since nothing can defend against you i laugh in your face and begin to slowly cut you up with a +1 Butter Knife.

It doesn’t matter how much you cut and slice, for I amnigh omnipresent. If you try to strike me, I shall apprear over there. No, there! Over there! Nyah-nyah-nyah!

Ah, but now, each one is you. In fact, you get so confused trying to figure out which one’s the real you, your brain(s) explode.