People are saying that the Alolan forms of Muk and Grimer are based on oil spills and chemical sludge, but I think I discovered the true nature of their origin. Plot twist:
Biology and nature of Grimer and Muk: Part 1 | Pokémon Amino
Grimer Anatomy- Pokedex Entry by Christopher-Stoll on DeviantArt
Grimer (Pokémon) - Bulbapedia, the community-driven Pokémon encyclopedia
Gen VII] Shiny alolan Grimer after around 100 SOS calls, made my safari week losses feel better, and the nature isn't half bad either: ShinyPokemon
Smogon University - Little Cup runneth over with cute and cuddly Pokemon, but today's spotlight Pokemon might not be one of them! Alolan Grimer's great typing, good natural bulk, and high Attack
Alolan Grimer's 3D model seems to be much smaller than normal Grimer's : r/TheSilphRoad
Grimer | Pokémon Wiki | FANDOM powered by Wikia | Pokemon, Type pokemon, Pokemon pokedex