Since it doesn’t seem like anyone’s given an appropriate source for this wonderous monster…
You can find it in Kobold Press’s Creature Codex! That book and it’s predecessor, the Tome of Beasts, are awesome 3rd party monster addons that we wholeheartedly recommend!
Don't give up. Unless you have to for a little while. Then don't panic. CONTAINS: Star Trek, Dungeons and Dragons, Critical Role, History, Current Affairs, Space, Cats, and Etc. Adult.