What happened to my Minecraft?

I'm currently playing version 1.8.9 and the following happened with the NORMAL version, without mods (see picture)

I have no idea how this happened and I don't want to either. Could it be that I was hacked and mods were added from another PC? I also have a profile for 1.8.9 where I have mods, but I never downloaded these ears and the cape was just for me. So can I somehow delete the mod files?

Could be deathmaus ears! Possibly. They are not completely out of the game files and are somehow bent into your version. Restart minecraft and see if it's still there!

Maybe a feature of the server. Or is that on every server?

Is that the hypixel bed wars server?

If it applies to every server then it's a mod. If it's just that server then it's a server cosmetic. You can delete mods in %appdata% .minecraft and then mods

there should be a 1.8.9 folder there inside the mods folder