I had a bunch of these I won at a carnival. Don't know if they were just knockoffs or what. Then I came across bags of them at a flea market a few months ago and thought it was weird that they'd be "collectible". Now I know they actually had a name.
These were a HUGE part of my childhood. My cousin and I traded them like baseball cards - some were def. cooler than others.
We would then set them up on our He-Man castles (large plastic playstations for your He-Man figures). I usually defended Castle Greyskull. So we would set them up, you had to have at least 1/3 of their body showing. We would then shoot at each others muscles w/rubberbands, last one w/a muscle standing was the winner. Good memories.