Ok one more, I can't help myself.

This one isn't really a manipulative parasite, but there is an isopod that will eat a fish's tongue: https://oceanconservancy.org/blog/2022/04/28/tongue-eating-l...

What's weird is that it then... basically acts like a tongue? It doesn't seem to be massively detrimental to its host, but it's absolutely insane to see a fish's mouth open and then there's just like, a little guy hanging out in there.