Unfortunately you can’t add alt text on Lemmy yet, I just did a spoiler which you can make by formatting your text like this Which looks like this to you:

And I added the image in my first comment because the custom hexbear emojis look really massive and make it hard to read threads when viewed from other instances due to some slightly hacky workarounds that were made so that hexbear could federate with the rest of lemmy but still keep all of it’s special features (well, most of them at least) since it runs on a fork of lemmy that no other instance uses rn (our admins are apparently working to try and fix the problem)