

Perfectly fine. Bumps don’t do what they used to do in messageboard/BBS contexts, so if you have something useful/clever/funny to say in a dead thread I say go for it.
Heck, sometimes it can prompt a follow-up when someone says “You know, I should do [x related to topic]” after some time has passed, which is fun.
To have some visuals added to this, either a trippy slideshow-esque video played silently, or do the whole album-synced-up-to-a-movie thing (Dark Side of Oz style).
Joined a Telegram group a while back with lots of ideas /materials for that last concept, so let me know if you want some inspiration.
Edit: A weird animation Youtube autoplay queue while playing solid music is a good choice too. Ideally this is all just in the background while hanging out/doing other stuff and just gives something to zone out on in between.