Aquadiversity Steward

{g/u}{g/u}: Aquadiversity Steward becomes a Merfolk Scout with base power and toughness 2/2 and hexproof.
{g/u}{g/u}{g/u}{g/u}: If Aquadiversity Steward is a Scout, it becomes a Merfolk Druid Scout with base power and toughness 4/4, hexproof, and "{t}: Add {g} or {u}."
{g/u}{g/u}{g/u}{g/u}{g/u}{g/u}{g/u}{g/u}: If Aquadiversity Steward is a Druid, it becomes a Merfolk Druid Scout Avatar with base power and toughness 8/8, vigilance, hexproof, and "{t}: Add {g}{u}."