Is he being hit by PK Thunder? Mewtwo's Shadow Ball? There are clear electrical properties going on but it's far too large to be PK Thunder and it's completely stationary. It also isn't clear if DK is conjuring it or whether he's being attacked by this mystical flow of energy.
It actually looks a hell of a lot like Pikachu's Final Smash introduced in Super Smash Bros. Brawl:
So what's actually going on in this scene, Era? It's been bugging me for years.