Leechridden Swamp is a uncommon Land — Swamp card from Shadowmoor (SHM), collector number 273. Current market price: $1.04 (foil $34.22), TCGplayer market prices via Scryfall.
({T}: Add {B}.) This land enters tapped. {B}, {T}: Each opponent loses 1 life. Activate only if you control two or more black permanents.