Rulings

• 2019-10-04
  If each target card is an illegal target by the time Lochmere Serpent’s last ability resolves, the entire ability won’t resolve. Lochmere Serpent won’t be returned.
• 2019-10-04
  If up to four of the target cards are illegal targets by the time Lochmere Serpent’s last ability resolves, the remaining legal targets are exiled and Lochmere Serpent is returned to your hand.
• 2019-10-04
  An Island is a land with the subtype Island, not any land that could produce blue mana. For example, Mystic Sanctuary is an Island, but Castle Vantress isn’t. Similarly, a Swamp is a land with the subtype Swamp, not any land that could produce black mana.
• 2019-10-04
  Activating Lochmere Serpent’s first activated ability after it has become blocked won’t cause it to become unblocked.
• 2019-10-04
  You can’t activate Lochmere Serpent’s last ability without targeting five cards in a single opponent’s graveyard.