I'm sort of surprised that Unmasked Twisty, which was a 2015 SDCC exclusive, is less valuable than Twisty, which was a common.

I'm not usually surprised when a pop doesn't go up in value as much as I'm shocked when they do. I started collecting horror pops when they first came out and now some of them are now insanely expensive. My most valuable pop has gone up in value by $200 since I bought it, which is nuts.