Shelldock Cradle enters the battlefield tapped unless you sacrifice a basic land.
: Add or to your mana pool.
Put Shelldock Cradle on top of your library: Add to your mana pool.
: Return Shelldock Cradle to its owner's hand.
: Add 
or 
to your mana pool.
to your mana pool. : Return Shelldock Cradle to its owner's hand.
