(: Add or to your mana pool.)
Shelldock Underground enters the battlefield tapped unless you sacrifice a planeswalker.
: Shelldock Underground becomes a 2/1 blue and black Cephalid creature until end of turn. It's still a land.
: Add 
or 
to your mana pool.): Shelldock Underground becomes a 2/1 blue and black Cephalid creature until end of turn. It's still a land.
