(: Add or to your mana pool.)
When Obsidian Coliseum enters the battlefield, sacrifice it unless you pay .
: Obsidian Coliseum becomes a 2/2 blue Cephalid Merfolk creature until end of turn. It's still a land.
: Add 
or 
to your mana pool.).
: Obsidian Coliseum becomes a 2/2 blue Cephalid Merfolk creature until end of turn. It's still a land.
