fake bills are remarkably common in circulation. I got two from an ATM at my local bank. Tried to use one at a grocery store where it was fond with the magic pen. They let me take it to my bank where it was exchanged for a real $100. Happened again and the same result from my bank only I found the second one immediately when it was dispensed from the atm.
Whoever owns the atm sounds like they should reimburse you if you have the receipt and whatnot
Wait, there are ATMs that spit out $100 bills? I guess my neck of the woods is low-rent, because they only spit out $20s around here.