There used to be a pets plugin on the server way back when for premiums to use. It just summoned an entity and didn't have any combat abilities, purely a cosmetic that followed you around. Said plugin was removed due to it being old and outdated. I'd like to suggest adding back such a plugin to the server, and found one called SimplePets that I looked at before: https://www.spigotmc.org/resources/simplepets.14124/
