(: Add or to your mana pool.)
Seafloor Den enters the battlefield tapped.
: Seafloor Den becomes a 2/1 blue and white Merfolk creature until end of turn. It's still a land.
: Add 
or 
to your mana pool.): Seafloor Den becomes a 2/1 blue and white Merfolk creature until end of turn. It's still a land.
