There's something I've been thinking of that seems like such an obvious joke that I feel like it must have been done, probably many times, but I can't find any examples: Anon has a conversation with Luna and gets into a who's-on-first-style misunderstanding because when she asks his name and he says "Anon" she thinks he's using the Elizabethan word.

Can someone point me to an example of this?

I think
(1) a pun
(2) requiring knowledge of and caring about Elizabethian English
isn't going to go over all that well with most of the fimfic audience.