Clever things to put on the back of a shirt?

Me and my friends are making a shirt for our math teacher because we are leaving his class, he is kindof a "ninja" so on the front of the shirt it will say "Ninja cleverly disguised as a math teacher" and on the back we would like to put the names of all the people who helped pay for it, but we want to put something clever and ninja-like, such as "Summoned to you by your ninja masters ___, ___, ___, ___.." ect. Please help!!!