Yes, this one is easy kids. Head down to your local thrift shop and grab some of the brightest, ugliest clothing you can find that's 1 size too small. Then find some big ugly glasses, punch out the lenses and snort a line of crystal meth (actually don't do that) and BOOM. You are the Red Foo yo!
The Guilty Remnant - From The Leftovers on HBO
Ok, so not everyone will get this but enough people will and they will think you are very clever. Maybe. What's great about this costume is that you probably already have it at your house. You just need an all white outfit, some cigarettes and a note pad. The guilty remnant more or less chain smoke and only use their note pads to communicate. No talking kiddies, just drinking and writing. The drunker you get, the funnier it gets.
A Mainstream "EDM" DJ
This one is also easy. Grab a black tight fitting T-shirt and cut the neck out of it so you have a HUGE scoop neck, really exaggerate this. Then find some tight black sweats, black sneakers and a black leather jacket. You are almost there.
Next grab some cheap huge black plastic fauxsigner shades, a huge bottle of hair gel and spike that shit up, sideways and all over the place. Congratulations, you are now a mainstream EDM DJ tool.
This one is also easy, just grab a white bucket, and and all white outfit (see above, you can also flip back and forth as guilty remnant). Take the bucket and punch in some small eye holes and take a black sharpie and sketch out the Marshmello face. Ouila! You are Marshmello!
A Rubber Tree
Ok, so this one is a clutch classic. Dress up in all green, preferably dark green if possible. Brown will also work. Then go find some leaves, buy two packs of condoms and get some good clear tape. Start taping the leaves and condoms to your body and you are a walking birth control dispenser or as you will explain, a rubber tree. Be careful because you will start to lose all your rubbers the later it gets. Mind the aggressive drunk bros!