Amethyst Dragon // Explosive Crystal

If an effect instructs you to choose a card name, you may choose the alternative Adventure name. Consider only the alternative characteristics to determine whether that is an appropriate name to choose.

You choose how many targets Explosive Crystal has and how the damage is divided as you put the spell on the stack. Each target must receive at least 1 damage.

If some of the targets are illegal as Explosive Crystal tries to resolve, the original division of damage still applies and the damage that would have been dealt to the illegal targets is lost. It won't be dealt instead to a legal target.

You must still follow any relevant timing rules for the permanent spell you cast from exile. Normally, you’ll be able to cast it only during your main phase while the stack is empty.

An adventurer card is a permanent card in every zone except the stack, as well as while on the stack if not cast as an Adventure. Ignore its alternative characteristics in those cases. For example, while it’s in your graveyard, Altar of Bhaal is an artifact card whose mana value is 2.

If an adventurer card ends up in exile for any other reason than by exiling itself while resolving, it won’t give you permission to cast it as a permanent spell.