You have your t-shirts, sweatshirts, keychains, mugs and all of the normal theme park merch anyone might buy to remember a park and show off to friends, but sometimes you see something weird in a gift shop that catches your eye because it's out of the ordinary. The question is what I'd theme park merch have you seen. For me, it's not necessarily at the theme park, but with the Six Flags photo pass you can get customized Souvenirs with your picture on it. I think some of their offerings went a bit overboard. Apparently you could get a shower curtain, a tablecloth or a towel with a picture of you (at Six Flags) on it! Who is the weirdo that wants a shower curtain with a picture of them, or wants to dry themselves off with a picture of themselves? I don't understand. It must make some money or else they wouldn't sell it. So, what odd park merch can you think of?
The classic is the shop underneath flying machines at Blackpool Pleasure Beach sells used parts from all the rides. Easiest way to buy yourself a coaster wheel / Chain link!