Buy @ TCGplayer
This spell costs {1} less to cast for each land your opponents control that could produce {C}.
Flying
When Obsidian Charmaw enters the battlefield, destroy target nonbasic land an opponent controls.
Obsidian Charmaw's first ability counts each land your opponents control that would produce {C} if one of that land's abilities resolved. It doesn't matter whether that land's controller could currently activate the ability or not.
