Does your setting have any "cryptids"?

I'm not just referring to magical animals here. I mean (possibly supernatural/occult) creatures that scholars debate the existence of.

An example from my setting would be the Luvvie. It's a shape-shifting humanoid that stalks a singular target for several days, learning as much as it can about them and slowly copying the target's appearance before striking. Here's the twist, though: once a Luvvie kills and replaces its target, it just tries to live a normal life as if it were the person it killed. It's murder is one-and-done. Whenever someone seems to be acting strange on the frontier, people might accuse them of being a Luvvie.