Each booster box contains 36 packs of Obsidian Flames
You can only use this effect of "Black & Blue Skull Dragon" once per turn
Incapsula incident ID: 569000121306597576-1403817710071644979
Of course, in the right deck, just letting the demon sit around and not attack can also be dangerous, as it turns on Spectacle powerhouses like Light up the Stage, Skewer the Critics, and Theater of Horrors
(2023-06-16) The trigger event doesn't have to specifically refer to legendary permanents or to artifacts, nor does it have to specifically refer to when something "leaves the battlefield." For example, an ability that triggers "whenever a creature dies" would trigger twice if a legendary creature or an artifact creature dies while Gandalf the White is on the battlefield, as would an ability that triggers "whenever a permanent is put into a graveyard from the battlefield." (2023-06-16) Look at each legendary permanent and each artifact as it exists on the battlefield, taking into account continuous effects, to determine whether any triggered abilities will trigger multiple times