In Mixels unite, Booger would have joined the N-Mixel Armada after his friends left him resulting to him having an inflated ego. I'm not making this up Source: https://www.deviantart.com/koolkidtwelve/journal/The-petty-reason-Booger-joined-the-N-Mixel-Armada-901025321 It is in the comment section
Credits to The Mixels unite team and the creators of Mixels (John Fang and David P. Smith)
