Alan, Soothsayer of Doom

When Alan, Soothsayer of Doom enters the battlefield, you may search your graveyard for a Forest, Island, or Plains and cast it onto the battlefield.
Discuss Global Warming: {t}, choose Forest, Island, or Plains; create {c} for each basic land of that type that an opponent controls. Use mana generated with this ability only to cast colorless spells.
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