Leshrac's Sigil is a rare Enchantment card from Secret Lair Drop (SLD), collector number 1188. Current market price: $1.84 (foil $2.67), TCGplayer market prices via Scryfall.
Whenever an opponent casts a green spell, you may pay {B}{B}. If you do, look at that player's hand and choose a card from it. The player discards that card. {B}{B}: Return this enchantment to its owner's hand.