I can kill bugs with a stare! But only they're staying still and are fleas.

I can emit light!

But only in a fully lit room... ;w;

I can shapeshift! But only when nobody's around.

I can speak any language known to man, but only to cats.

I can preach the truths of the world, through my cardboard cutout and my stuttering speech at the side of the road.

BAHAHA I LOVE THIS THREAD!
IT IS HILARIOUS!

Oh man, there's a website like this, though I dunno if it was mentioned here or not. My friends and I went through dozens. XDD

My personal favorite:

I have the power to lengthen my arms as long as I'd like, but they can never go back to normal size.

I can grow my fingertips, but it takes a week and they break if i scratch someone.

The ability to move faster than the speed of light, but I can't see where I am going.

I can fly, but only in an airplane.

I can communicate with nearly everyone on Earth, I just need their phone number...

I can talk to the dead, but it seems they don't talk back.

I'm the best at stealthiness but only when somebody is watching me.

I can cut anything, but only if I have a sword