At the beginning of your end step, if you didn't cast any spells this turn, Tidal Karst deals 1 damage to you.

, Pay 1 life: Add  or to your mana pool.

, , Sacrifice Tidal Karst: Draw a card.

: Tidal Karst becomes a 1/1 green and blue Merfolk Shapeshifter creature with flying until end of turn. It's still a land.