The Final Fantasy Universes Beyond set chose to represent crystals as a new artifact cycle, which combine useful cost reduction with powerful passive and activated abilities
You might also enjoy our guide to the most expensive MTG cards ever sold
If the top card of your library changes while you're casting a spell, playing a land, or activating an ability, you can't look at the new top card until you finish doing so
Then, for each nonland card thats milled that way, they lose one life and remove a rad counter
It uses a modified version of the Champion mechanic, requiring you to Behold a Goblin to cast it, which protects a key utility piece by exiling it until the Champion leaves the battlefield
Five mana is a bit steep but in the late game it matters a lot less about the cost and a lot more about the immediate impact, this flexibility makes the card much stronger rather like Mull Drifter which is somewhat of a back up plan in one of its curve slots