Snow Fortress is a rare Artifact Creature — Wall card from Ice Age (ICE), collector number 337. Current market price: $0.62, TCGplayer market prices via Scryfall.
Defender (This creature can't attack.) {1}: This creature gets +1/+0 until end of turn. {1}: This creature gets +0/+1 until end of turn. {3}: This creature deals 1 damage to target creature without flying that's attacking you.