Regicide is a common Instant card from Conspiracy: Take the Crown (CN2), collector number 45. Current market price: $0.10 (foil $0.72), TCGplayer market prices via Scryfall.
Reveal this card as you draft it. The player to your right chooses a color, you choose another color, then the player to your left chooses a third color. Destroy target creature that's one or more of the colors chosen as you drafted cards named Regicide.