Contagion Clasp is a rare Artifact card from Friday Night Magic 2011 (F11), collector number 10. Current market price: — (foil $5.69), TCGplayer market prices via Scryfall.
When this artifact enters, put a -1/-1 counter on target creature. {4}, {T}: Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)