It's normally how I get stuck in fandoms in the first place: lurking on YT/Tumblr, seeing something that I might like [for example, DW is cute Mascot Horror. I like cute stuff], and trying as hard as possible NOT to get stuck.. only to fail once I smile and think "hey, this is cool".
Some hyperfixations take more time than others to hit, and if they get stuck in my brain, it's hard to get them to leave.