Raucous Theater is a rare Land — Swamp Mountain card from Murders at Karlov Manor (MKM), collector number 329. Current market price: $14.98 (foil $28.43), TCGplayer market prices via Scryfall.
({T}: Add {B} or {R}.) This land enters tapped. When this land enters, surveil 1. (Look at the top card of your library. You may put it into your graveyard.)