>>30421339>>30421382>>30421359Wicke's dex entry says toxapex leaves a trail of corsola bits behind it wherever it goes.
However if you go to the beach where Kukui's lab is you can find 2 injured corsola that you can heal with a potion or carry to the pokemon center.
If you try to do either their owner appears and says she had to rush to the pokecenter for a minute, and explains something about mareanie eating corsola's branches, and while corsola doesn't die, the experience is scary for it.