(Watery Watchtower isn't a spell.)
When Watery Watchtower enters the battlefield, you lose 2 life unless you reveal a Merfolk card from your hand.
, : Scry 2.
: Add or to your mana pool.
Sacrifice Watery Watchtower: Add or to your mana pool.
, 
: Scry 2.: Add 
or 
to your mana pool. or to your mana pool.
