Obsidian Charmaw
Creature — Dragon
This spell costs 
less to cast for each land your opponents control that could produce 
.
Flying
When this creature enters, destroy target nonbasic land an opponent controls.
Lucas Graciano
Modern Horizons 2 (MH2)
• #137Rulings
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.
(wotc • 2021-06-18)
Rulings
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.
(wotc • 2021-06-18)