>>58758547seeing her in mega blastoise makes sense, her only real use is with stage 2 megas that you'd want to rare candy into. being ran in lopunny/lucario is surprising though, between copycat and may stage 1s are easy to get online. i would never consider serena for that type of deck.
she's not a garbage card like some people are claiming, she's definitely around will tier where she's only useful in a small fraction of decks (deck has a mega, not a basic mega, not a stage 1 mega, not a stage 2 mega that goes through the stage 1 like zard or venu) but she's good when your deck does meet that criteria. still, that's not good for her trade value.
