>>27266588>why wouldn't it?Mimikyu exists separately from the Pikachu costume though. Just because the ghost under the costume hatches shiny doesn't mean it'll find a shiny pikachu costume. Pikachu pokedolls might not even be made in shiny colors in the world of Pokemon.
Of course there's other shiny pokemon that don't make sense if you consider their dex entires - Slowbro, Kangaskhan, Dugtrio and Magneton to name a few - but even in those cases it's another pokemon that shouldn't be shiny. Mimikyu's Pikachu costume is a separate inanimate object. It doesn't even have any DNA to BE shiny.
Well, at least hopefully it doesn't.