Funny Ninja Joke Trucker Hats! Buy the funny ninja joke "Warning: I have mad ninja skills" on a fun selection of trucker hats from our collection in fun colours. Fun novelty ninja joke trucker hats for ninja geeks. With the cool joke "Warning: I have mad ninja skills", theses trucker hats are great for summer and a must have to show off with at the next anime-con or comic-con! Buy your own funny ninja joke trucker hat today! Remember the bulk purchase discount too: the more you buy, the more your savings!