Review (5/5): Comes out in a single washing!
I wanted bright yellow hair for a Ron Stoppable cosplay. I have brown hair, so I was advised to apply a layer of white first, then yellow on top of that so it would be intense and bright. This stuff worked great! It's definitely gel -- your hair is going to take whatever shape you give it and stay there -- but even with two colors/layers of the stuff, it all washed out in about 30 seconds when I jumped in the shower and hit it with shampoo that night. Very impressed!