Bitten by a radioactive Mamiya as a toddler.
Err,
Well, you see, one day, at a tender young middle-school age, RatmagicGirl, while long since having been expected back in class, was on the run from some school administrators, custodial staff, some older kids with a vehemently different opinion about the worthiness of a few of her immigrant friends, and a rather tightly-wound librarian that she introduced the former to by way of a bit of diversionary action... Success! Dah-da dah! But for how long? Quickly, she doubled back past the whole scene and into a bolthole she knew of... *click* Ooops...
This time, rather than the usual closet-like blackness, the light was kind of amberish in there. And there was this older girl in there who didn't turn me in.