Mimic of Storm Cavern

Prismatic (This card is all colors at all times.)
As long as this card is in your hand, your library, your graveyard, exile, or the command zone, it is a copy of the last nonland card you cast this turn. (If it is moved from one of those zones onto the stack as a spell, it becomes whatever it was copying beforehand until it is moved back to one of those zones.)
"Every adventurer to travel int