If you don't cast the card using its miracle ability, it will remain in your hand
This highlights the importance of including some decent green card draw in your decks
In Magic: The Gathering, where the collector market considers cards to be investments it's frankly barbaric to play an actual game with, the equivalent is an unofficial format called Sharpie Cube, or Redacted Cube
Ive put decks together for them a few times recently, but since I dont play tournaments in either format regularly
This thing loves blink and midrange that loads down decks with ETB stuff as well the needed triggers of dying things in Aristocrats and Sacrifice-matters, Artifact decks, even a Solemn Simulacrum that most run is quite doable
The December preview gave us a pretty good idea of what to expect for this collaboration