Mac Tonight was a character introduced back in 1986 to help sell the "late night" menu at McDonalds. He was a crescent-moon-headed lounge singer, and he was cool.
Back then, my friend Rick and I became a bit obsessed with this character, mostly because we decided that he appeared to be some demonic-headed pagan god in modern dress. Yes, to us Mac Tonight was a freaky dude with superpowers.
This sticker was probably used in-store and stuck on "to go" bags and the like. I'd actually been looking for any kind of Mac Tonight sticker for the last year, and this popped up as part of a small MT lot on Ebay a few weeks ago. Got it cheap, and now I can share it with you all here.
According to the Wiki entry, Mac Tonight is the only McDonalds character that's never appeared with the McDonaldland gang. Interesting. Might be time for a McDonalds Earth 1 and Earth 2 crossover.