The possibility that any card in Historic can be retroactively rebalanced, nerfed, or fundamentally changed at any time throws Historic deck-building into volatility, and opens the otherwise static format to unanticipated changes
This gives you the resources to draw a bunch of cards as long as your deck has a bunch of creatures
(If this creature isn't monstrous, put three +1/+1 counters on it and it becomes monstrous.) When this creature enters or becomes monstrous, exile up to two target artifacts and/or enchantments controlled by different players
The Power Nine were only printed for the very first core card sets, and the group includes the Black Lotus, Ancestral Recall, Time Walk, Timetwister, and the Mox jewel cards: Mox Pearl, Mox Ruby, Mox Emerald, and Mox Jet, as well as the Mox Sapphire