a white plastic bag, turned inside out with a drawing of a skeleton on the body of it, only at the time I didn't know much about biology - and yes, it was I doing the drawing, and so I ended up with mostly ribs - all the way to my knees, and then ran out of the black marker I was using to block out the back ground, so ended up not going out trick or treating at all that year.
a black plastic bag, with squashed up beer and cider cans, used, unwashed (and many having been used as ashtrays) - all sellotaped around the entire covering of the bag. It was highly impractical, smelly, and uncomfortable when sitting down. In the nightclub people were grabbing at the cans, thinking they might be full - I ended up losing the whole outfit - thankfully had my fall back plan, "disco attendee" outfit on underneath.
So now - I've shown you mine... what were the worst for ye??
Rachel F - you are excused from this exercise :-)