Alolan Spewpa
Bug/Steel
Ability: Shell armor or overcoat
Due to the lack of horned beetle like pokemon in the Alola region, scientists were baffled by the presence shelmets evolved form, accelgor. Tests were run to see if there were secretly any karrablast in the region or if there was a way for accelgor to arrive on the islands from elsewhere, but both hypotheses were debunked. Upon further research, the culprit was found to be an unassuming spewpa clad in an armor like cacoon made from a mixture of silk and stolen shelmet shells. Due to the lack of predatory Karrablast the usually timid scatterbug had apparently changed to use its silk and steal shelmets shell for its evolution. Some scatterbugs went so far as to attack shelmets in the relative safety of the marshes for their evolutions. Upon evolution, the scientists were disappointed to find that the alolan spewpa evolved into a regular ocean pattern vivilion.
Based on the lesser known hawaiian snail eating carnivorous caterpillar.
https://en.wikipedia.org/wiki/Hyposmocoma 