What freakish mutations and unusual abilities or traits do you have?
I've got a pretty long list of them, but one of the more fun ones is my immunity to extreme temperatures. My skin has some weird insulating properties which makes me extremely resistant to not only extreme heat and cold, but electricity as well. I can work a fire without tools, I can walk barefoot through the snow for at least an hour (probably a lot longer, if not indefinitely. that's just the longest I've tested it), and I can withstand shocks that would cause involuntary muscle spasms in a normal person while feeling only a pleasant tingling sensation.
In addition, my body produces enormous amounts of heat (a side effect of my incredible metabolism) which when combined with my freakish skin allows me to survive in the kind of cold that only a polar bear and flaming penguin can take. Of course, that makes it hard to remain in a warm environment. In the winter, I have been known to roll around in the snow to cool off after being inside a warm building. In the summer I carry ice packs in my pockets, cover myself with water, and do whatever it takes to stay cool. Honestly, if it's more than 5-10 degrees above freezing, I don't like it.
I am hoping that some day I will be able to harness all this heat and cover my body in fire like the human torch. And when that day comes, I will unleash a terrible vengeance on my enemies, and make delicious smores for my friends. You have been warned.