Kicker {1} (You may pay an additional {1} as you cast this spell.)
When Tide Shaper enters the battlefield, if it was kicked, target land becomes an Island for as long as Tide Shaper remains on the battlefield.
Tide Shaper gets +1/+1 as long as an opponent controls an Island.
A land that becomes an Island gains “{T}: Add {U}” and loses all other abilities. It loses any other land types, but it doesn't lose any types or supertypes, such as creature, legendary, or snow.
If Tide Shaper leaves the battlefield before its triggered ability resolves, the target land will not become an Island.
Tide Shaper will get +1/+1 as long as an opponent controls any land with the Island land type, not just ones named Island.