Virulent Silencer is a uncommon Artifact Creature — Robot Assassin card from Edge of Eternities (EOE), collector number 248. Current market price: $0.26 (foil $0.35), TCGplayer market prices via Scryfall.
Whenever a nontoken artifact creature you control deals combat damage to a player, that player gets two poison counters. (A player with ten or more poison counters loses the game.)