A girl you legitimately cannot understand, but not in a bad or offensive way, but she is simply peculiar to your mind. If angered enough she could become dangerous and needs to be secured, contained, and protected (well more so others need to be protected)
Terry: Have you seen Emily?
Bob: Yeah, she's a literal SCP, she's into such odd things, and I heard she held a knife to her boyfriend because he was two minutes late home.
Dan: Wow, she is wild. Somehow Kenny is still with her. I wish it was me.
Terry: Boy shutcho bitchass up we all know you have a fetish for that BDSM-ass shit