Corpse Traders

{2}{B}, Sacrifice a creature: Target opponent reveals their hand. You choose a card from it. That player discards that card. Activate only as a sorcery.

Jumpstart

Duel Decks: Jace vs. Vraska

{2}{B}, Sacrifice a creature: Target opponent reveals his or her hand. You choose a card from it. That player discards that card. Activate this ability only any time you could cast a sorcery.

Avacyn Restored

You can sacrifice Corpse Traders to pay the cost of its ability.

If you cast this as normal during your main phase, it will enter the battlefield and you’ll receive priority. If no abilities trigger because of this, you can activate its ability immediately, before any other player has a chance to remove it from the battlefield.