(: Add or to your mana pool.)
At the beginning of your end step, if you didn't cast any spells this turn, Obsidian Volcano deals 1 damage to you.
: Obsidian Volcano becomes a 2/1 black and red Skeleton creature until end of turn. It's still a land.
: Add 
or 
to your mana pool.): Obsidian Volcano becomes a 2/1 black and red Skeleton creature until end of turn. It's still a land.
