Giant Slug
Chronicles — common
Creature — Slug
Giant Slug rulings:
2004-10-04: If the Slug changes controllers after the mana is spent, the player who activates this ability selects a landwalk during their next upkeep even if they don’t control it at the time.
2004-10-04: When the ability resolves, it creates another ability that triggers at the beginning of your next upkeep. When that ability resolves, you choose a basic land type.