The Will to Power... and Carry Nunchucks!

In the car yesterday, and unexpectedly philosophical conversation with my children:

Daughter: My seat's too hot! My seat belt's too hot, too.
Me: Well, you remember what Friedrich Nietzsche said: "That which does not kill me makes me stronger."
Son: Which ninja said that?
Me [trying not to crash the car]: It was... umm... Friedrich.
Son: I think he's the blue one.
Daughter: Why are you coughing, Daddy?

I like to think this is the first time "Nietzsche" and "ninja" have been conflated, but Nietzche's work does have a certain ninja-like quality about it.