Siege of Towers is a rare Sorcery card from The List (PLST), collector number GPT-76. Current market price: $0.09, TCGplayer market prices via Scryfall.
Replicate {1}{R} (When you cast this spell, copy it for each time you paid its replicate cost. You may choose new targets for the copies.) Target Mountain becomes a 3/1 creature. It's still a land.