UPDATE - 11/28@4:42PM: Here's a photo of Peter Criss with Rush taken from the book. Thanks to Ethan G for the scan and RushFanForever for the heads up.
Former KISS drummer Peter Criss recently released his new autobiography Makeup to Breakup: My Life In and Out of Kiss and tells a funny story involving Rush on pages 330-31:
... When we first started headlining, we toured with Rush. Gene and Paul were more standoffish, but Ace and I really became good friends with them. They were good old Canadian boys who liked to smoke pot and drink scotch, really down-to-earth guys. And they came up with a character that they called the Bag. One of them would put a large brown paper bag over his head. Then they drew a face on the bag and they cut out eye holes so that, if whoever was under the bag was smoking a cigarette, smoke would come out one of the eyes. It looked very creepy. The Bag was very rude and nasty to women. So we'd invite him to the party just to cause chaos and anarchy. He'd come in and start insulting the women who were there, calling them whores and sluts. ...
Ace Frehley also mentions The Bag in his autobiography No Regrets that was released last year. Peter Criss's version gives a lot more detail, but in Ace's version he attributes The Bag idea exclusively to Alex Lifeson. You can read Ace's version of the story in this post and order Peter's book on Amazon here. Thanks to Twon for the heads up.