Belle's androgyny idea is on point, and has the huge advantage of being inexpensive and relatively easy to do. Be the dude version of Purple T. You can get your clothes at a thrift store. Also, you can use ordinary makeup to create a very realistic five-o'clock shadow, if you don't want to do a full fake 'stache or beard. You will rock that thing, T.
rock up wearing something u wouldn't usually. say u don't wear much makeup, put a ton of it on, even behind the mask. do ur hair a completely different style, or wear a dress style that you've never worn before. that way people won't expect it's u.
Wear a wig, wear a paper bag that says I AM NOT PURPLE T, become androgynous, investigate prosthetic makeup, do one of those scary full face make up looks, or maybe the multiple feature thing where you have like 3 mouths and six eyes?