www.youtube.com/watch?v=Hn70Lz6uIDs
I just got this game, and discovered that Valkyrie (from The Legend of Valkyrie) is a support character introduced in the fourth prologue level, and her support attack end with her jumping high into the air, using her Big Magic, and butt-stomping the enemy Mario-style. You can see it at 0:35 in this video. The growth happens offscreen, sadly, but at least you can see her shrink back to normal size after she does it.