Sure, when your ancestors aren't sticking their hands in them to prove they're worthy of not getting exiled from the clan after being dishonored.

[Which is hard to do for ninjas. Their code is waaay less noble than, say, bushido. But his ancestor went and did it. Somehow.]

That's why I look like this. He got stung by something and it passed down. Everyone that's born into my family looks like this, even if normal people marry in. Like my mom.

[He shrugs.]

Still, it's kinda cool. But I guess a booby trapped cave ain't bad. You still haven't explained how your clan learned ninjutsu, though.