The First Sliver Mirrodin Besieged there is an additional beginning

there is an additional beginning phase after this phase

each commander creature you control deals damage equal to its power to that creature

a player puts the top card of their library into their graveyard

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−3: Exile target creature

The First Sliver Mirrodin Besieged there is an additional beginningCascade (When you cast this spell, exile cards from the top of your library until you exile a nonland card that costs less. You may cast it without paying its mana cost. Put the exiled cards on the bottom in a random order.) Sliver spells you cast have cascade.