Blast Zone is a rare Land card from Secret Lair: Ultimate Edition (SLU), collector number 504. Current market price: — (foil $0.76), TCGplayer market prices via Scryfall.
This land enters with a charge counter on it. {T}: Add {C}. {X}{X}, {T}: Put X charge counters on this land. {3}, {T}, Sacrifice this land: Destroy each nonland permanent with mana value equal to the number of charge counters on this land.