Dimir Infiltrator is a common Creature — Spirit card from Planechase 2012 (PC2), collector number 86. Current market price: $1.01, TCGplayer market prices via Scryfall.
This creature can't be blocked. Transmute {1}{U}{B} ({1}{U}{B}, Discard this card: Search your library for a card with the same mana value as this card, reveal it, put it into your hand, then shuffle. Transmute only as a sorcery.)