While it’s unexpectedly quiet and friendly, if it’s not fed any trash for a while, it will smash its Trainer’s furnishings and eat up the fragments.
– Pokémon Moon Pokédex
Alolan Muk is Poison/Dark instead of pure Poison. It’s a pretty good type combination, being immune to Psychic and only weak to Ground. Its body is infused with many colours. According to its Pokedex entry, the colours are caused by chemical changes in its body from eating garbage. It looks meaner than Kanto Muk, probably because it’s Dark type?
Its hidden ability is Power of Alchemy, which is exclusive to it and Alolan Grimer. It makes Muk take on the ability of a fainted ally.
Stat-wise, it has good Attack, Sp Def, and HP, but low Speed. Alolan Muk actually has the same stats as Kanto Muk.