Prior art may go back further than the 1980s. I seem to recall that on some old MUDs, you could be “toaded,” or maybe “frogged,” which would make you look to others like a toad/frog, and anything you said would display as “ribbit” or something.
Usually they would know but there was a couple of MUDs that hid it. Of course you found out pretty quickly because everyone would find the hyperactive toad hilarious.
See https://en.wikipedia.org/wiki/MUD and https://publishing.cdlib.org/ucpressebooks/view?docId=kt367n...