When Tidehollow Sculler enters, target opponent reveals their hand and you choose a nonland card from it. Exile that card. When Tidehollow Sculler leaves the battlefield, return the exiled card to its owner's hand.
{T}: Add one mana of any color. Spend this mana only to cast a creature spell.
Leylines branch out from its foundation like roots from a tree. These draw mana from every region and welcome all living things into its verdant chambers.
Thawing Glaciers enters tapped. {1}, {T}: Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle. Return Thawing Glaciers to its owner's hand at the beginning of the next cleanup step.
Celestial Colonnade enters tapped. {T}: Add {W} or {U}. {3}{W}{U}: Until end of turn, Celestial Colonnade becomes a 4/4 white and blue Elemental creature with flying and vigilance. It's still a land.