Phyrexian Dreadnought | Magic: The Gathering
Formats Phyrexian Dreadnought is Legal in
Official Oracle Text for Phyrexian Dreadnought
When Phyrexian Dreadnought enters the battlefield, sacrifice it unless you sacrifice any number of creatures with total power 12 or greater.
Official Rulings for Phyrexian Dreadnought
10/4/2004 : Phasing in does not trigger "enters the battlefield" abilities, so you don't have to sacrifice again if it phases in.
7/15/2007 : Reverted to its original wording, this now has an enters-the-battlefield triggered ability. During resolution of the triggered ability, you choose one option or the other.
7/15/2007 : If the Dreadnought is no longer on the battlefield when the triggered ability resolves, you may still choose either option.
4/15/2013 : If you are unable to sacrifice 12 power worth of creatures, then you cannot choose that option; in that case, you must sacrifice Phyrexian Dreadnought.