Mogg Assassin is a rare Creature — Goblin Assassin card from Secret Lair Drop (SLD), collector number 2517. Current market price: $2.54 (foil $2.44), TCGplayer market prices via Scryfall.
{T}: You choose target creature an opponent controls, and that opponent chooses target creature. Flip a coin. If you win the flip, destroy the creature you chose. If you lose the flip, destroy the creature your opponent chose.