>>55262870>>55262875>>55262881Slowbro can Mega Evolve in GO, Galarian Slowbro can't.
In order to mega a regional, you'd need [Region-name][Poke]-ite.
See: Aloraichium Z, which works on Alolan Raichu but not regular Raichu. G-Slowbro would need Galaslowbronite.