Night Dealings is a rare Enchantment card from Champions of Kamigawa (CHK), collector number 132. Current market price: $1.33 (foil $17.06), TCGplayer market prices via Scryfall.
Whenever a source you control deals damage to another player, put that many theft counters on this enchantment. {2}{B}{B}, Remove X theft counters from this enchantment: Search your library for a nonland card with mana value X, reveal it, put it into your hand, then shuffle.