What to wear: Mystique, Storm, Jean Grey, and Psylocke costumes are the perfect way to be strong, empowered mutants on Halloween (psychic powers not included, sadly). Make sure your hair matches theirs (i.e., respectively slicked back and bright red, a white mohawk, long and red, and brown with purple streaks).
How to act: Each character has a unique personality, so you have some homework to do.