Buy @ TCGplayer
Whenever you draw a card, target opponent mills two cards. If two nonland cards that share a color were milled this way, repeat this process.
{5}{U}: Draw a card, then discard a card.
Colorless is not a color, so putting two colorless cards into a graveyard won’t cause the process to repeat.
The process will keep repeating as long as both cards share a color and neither is a land card.
