Conqueror's Flail is a rare Artifact — Equipment card from Secret Lair Drop (SLD), collector number 1571. Current market price: $13.41, TCGplayer market prices via Scryfall.
Equipped creature gets +1/+1 for each color among permanents you control. As long as this Equipment is attached to a creature, your opponents can't cast spells during your turn. Equip {2}