>>30409621The Mareanie that shows up will attack the Corsola, not the opponent (at least as long as the Corsola is around).
Even if you kill the Corsola before the Mareanie can act, it'll say that Bite has 'failed' rather than attacking you. What happens is not that Mareanie comes to help, but rather that it hears the sounds of a distressed Corsola and tries to take advantage of this opportunity to get some free food (eg the Corsola).
Same happens with Carbink, who can summon a Sableye which can try to Fury Swipes it.