Undercity Plunder
Sorcery
(CMC 2)
Target opponent discards a card. Then they may discard an additional card. If they don't, conjure a duplicate of a random card from their library into your hand. It perpetually gains "You may spend mana as though it were mana of any color to cast this spell."
- [YNEO] Alchemy: Kamigawa #15 (R)