Last minute Halloween costume idea? (I'm cheap, lazy, and about out of time)

So I was invited sort of last minute to a halloween party by a friend. Seeing as I wasn’t planning on going anywhere, I do not have a costume. Is it kosher attend without one (my friend doesn’t have one either)?

If not, are there any cheap/easy costumes I can throw together?

Old short-sleeved collared shirt (or long-sleeved, with the sleeves cut off ragged).

Make some fake cardboard shoulders that will support the shirt - attach these to a piece of stout card bent into a tube/ring that will fit on your head.

Make a gory-looking stump neck to go on top of the fake shoulders, to protrude up through the collar of the shirt.

Wear the fake shoulder contraption on your head, with the shirt draped over it - you may need to slit the underarms of the shirt vertically a little to get your arms through and out, but it should be possible to get a fairly convincing headless look this way - wear jogging bottoms that can be pulled up to compensate for the raised shirt (or use a long nightshirt or something).

Sacrificial white shirt, paint/crayon/marker large yellow circle on the belly part. Stop at the closest drugstore or KMart on the way to the party and buy the $9.99 devil horns and tail set. Poof: you’re a deviled egg.

Craze up your hair with whatever hair gel, spray or goop you have, stick it up in random spikes. Draw lightning bolt on cheek with eyeliner and safety pin socks, underwear and fabric softener sheets onto clothing. Poof: you’re static cling (and you’ll smell April fresh!)

Wear a plaid flannel shirt, make-up on some beard stubble and carry a little gardening hatchet. Poof: you’re a Very Ineffective Lumberjack.

Stick maxipads all over yourself with their adhesive and act stuck up. Poof: you’re Self-absorbed.

Buy a bag of Smarties. Affix them to your pants. Voila, you’re a smarty-pants.

I am currently wearing a costume that I threw together at 8PM last night, and I may win the costume contest at work today. I have on overalls, a plaid work shirt, and a ball cap worn backwards. I’m carrying a plunger and a pipe wrench, and I have a nametag on that says “Jo.”

Take a queen size sheet. Drape it over your head so that it hangs evenly front + back. Through the sheet, poke yourself in each eye, and your mouth with a felt tip marker/pen. Take sheet off. Use an overturned shot glass to mark a circle to cut out for each eye (use the pen marks as a guide for where the holes should be), and a highball glass/tumbler to cut out the mouth. Drink red wine all night, be sure to spill some on yourself (insta-blood!), esp around the mouth.
voila ghost!
Bonus points:
Tiedye sheet: Hippy ghost!
Monogrammed sheet: Preppy ghost!
Anime/superman/spiderman sheets: Stuck-in-high-school ghost!
Plaid sheet: Lumberjack ghost!

Bathrobe, slippers, pyjamas, towel, teacup, tousled hair, befuddled expression.

If you want to go all out, you can print up a dust-jacket that says “Don’t Panic” in large, friendly letters and wrap it around a handy “book.”

I’ve seen quite a few people do the ‘just woke up’ thing as their last minute costume. Mess up your hair, accenting it with shaving cream, gel, or anything else around the house that will make it look and stay exaggerated. Wear sleeping attire and a bathrobe…as well as slippers if you have them. Carry coffee mug with you. - and you’re done

Wear the rattiest clothes you can find, and wreck the rattiest them more tearing out the knees of the pants. Perhaps make a hat out of a piece of newspaper. - You’re a wierd homeless guy.

Make a large hat out of tin foil, wear it, and walk around the party telling everyone aliens and the CIA are trying to read your thoughts

You’re a dude, right?

Wear jeans and a wifebeater, or no shirt at all. Carry an open beer can, maybe have an unlit cigarette in your mouth. You’re the “star” of any episode of Cops

I needed something cheap and easy too. I pinned one leg of my pants up, then I pinned socks and things along with a few used dryer sheets to my clothes and came to work as someone afflicted with a horrible case of static cling.

White shirt with a filled in yellow circle on the tummy.

You’re a deviled egg!

This is probably too late for you, but in case anyone else needs an idea:

Dress normally. Put a sign on that says “Nudist on Strike.”

Damn, too bad I missed this. I was going to suggest using make up to fake bruises-especially black eyes-on your face, and a backwards “B” on your cheek. Voile! You’re Ashley Todd!

Yeah, too late, but I saw a great cheapo costume one time - a guy took a bag of those fake spiderwebs and draped them over himself (wearing normal clothes.) Spent a good amount of time sitting motionless in a chair. He won Creepiest Costume.