Cavern of Souls [The List] Basic Land Tap an untapped artifact you

Tap an untapped artifact you control: Add {U}

"In the drowsy dark cave of the mind dreams build their nest with fragments dropped from day's caravan

Set: Junior Super Series Type: Creature — Merfolk Rarity: Rare Cost: {U}{U} Other Merfolk get +1/+1 and have islandwalk

Set: IDW Comics 2012 Type: Instant Rarity: Rare Cost: {2}{U}{U} Choose artifact

Cavern of Souls [The List] Basic Land Tap an untapped artifact youSet: The List Type: Land Rarity: Rare As Cavern of Souls enters the battlefield, choose a creature type. {T}: Add {C}. {T}: Add one mana of any color. Spend this mana only to cast a creature spell of the chosen type, and that spell can't be countered.