Flying
At the beginning of your upkeep, mill a card. If an instant or sorcery card was milled this way, transform this creature. (To mill a card, put the top card of your library into your graveyard.) // Flying

"Metamorphosis is a process." —Laboratory notes // The final pages of the experiment log were blank. Investigators found it abandoned on a desk in the researcher's lab, open, the pages flipping in the wind from a shattered window.