Magmatic Core | Magic: The Gathering
Formats Magmatic Core is Legal in
Official Oracle Text for Magmatic Core
At the beginning of your end step, Magmatic Core deals X damage divided as you choose among any number of target creatures, where X is the number of age counters on it.
Official Rulings for Magmatic Core
7/15/2006 : If Magmatic Core has no age counters on it, the only number of targets the ability can have is zero.
7/15/2006 : If Magmatic Core has at least one age counter on it, the number of targets must be at least one and at most X. Each target must be assigned at least 1 damage.
7/15/2006 : Magmatic Core's effect is mandatory. At the end of your turn, if the only creatures on the battlefield are yours, you must have Magmatic Core deal damage to at least one of them.