Rime Transfusion is a uncommon Snow Enchantment — Aura card from Coldsnap (CSP), collector number 68. Current market price: $1.18 (foil $14.97), TCGplayer market prices via Scryfall.
Enchant creature Enchanted creature gets +2/+1 and has "{S}: This creature can't be blocked this turn except by snow creatures." ({S} can be paid with one mana from a snow source.)