Thoughtseize (Borderless Etched Foil) [Secret Lair Drop Series] BW39 {T}: You may put a

{T}: You may put a creature card from your hand onto the battlefield

Set: Sun & Moon: Cosmic Eclipse Type: Dragon Rarity: Ultra Rare Retreat cost: Colorless

Set: Black & White: Black Star Promos Type: Lightning Rarity: Promo Retreat cost: Colorless

and has "Whenever a player casts a spell or a creature attacks

Set: Scarlet & Violet: Temporal Forces Type: Neo Upper Energy Rarity: Rare Ace

Thoughtseize (Borderless Etched Foil) [Secret Lair Drop Series] BW39 {T}: You may put aSet: Secret Lair Drop Series Type: Sorcery Rarity: Rare Cost: {B} Target player reveals their hand. You choose a nonland card from it. That player discards that card. You lose 2 life.