It makes it wavy when it isn't already curled but if you put mousse on it when it is already been curled or curly then it acts like a hair spay and keeps it in for longer :)
Does Hair Mousse Make Your Hair Curly?
Mousse gives your hair body - Style it to produce curls or have straight hair.
Well mousse itself makes your hair kink a little. For the full effect of curly hair with mousse, you have to scrunch your hair with your fingers for it to be curly.
The chemicals in mousse seep into your hair follicle pores and can cause infections or cancer