Gemstone Caverns [Time Spiral Remastered] Murders at Karlov Manor Prerelease Promos it deals that much damage

it deals that much damage plus 2 instead

Whenever another creature dies

When Craterhoof Behemoth enters the battlefield

−7: You may cast up to three spells from among face-up cards your opponents own from exile without paying their mana costs

then attach this to it

Gemstone Caverns [Time Spiral Remastered] Murders at Karlov Manor Prerelease Promos it deals that much damageSet: Time Spiral Remastered Type: Legendary Land Rarity: Mythic If Gemstone Caverns is in your opening hand and you're not the starting player, you may begin the game with Gemstone Caverns on the battlefield with a luck counter on it. If you do, exile a card from your hand. {T}: Add {C}. If Gemstone Caverns has a luck counter on it, instead add one mana of any color.