Deeproot Waters

Oracle Text

Whenever you cast a Merfolk spell, create a 1/1 blue Merfolk creature token with hexproof. (A creature with hexproof can't be the target of spells or abilities your opponents control.)

Card Rulings

9/29/2017 The ability of Deeproot Waters resolves before the spell that caused it to trigger.
1/19/2018 If an effect refers to a “[subtype] spell” or “[subtype] card,” it refers only to a spell or card that has that subtype. For example, March of the Drowned is a card that benefits Pirates and features Pirates in its illustration, but it isn’t a Pirate card.