2011-06-01 : A card with Phyrexian mana symbols in its mana cost is each color that appears in that mana cost, regardless of how that cost may have been paid.

2011-06-01 : A creature’s mana value is determined solely by the mana symbols printed in its upper right corner (unless that creature is copying something else; see below). If its mana cost includes {X}, X is considered to be 0. If it has no mana symbols in its upper right corner (because it’s an animated land, for example), its mana value is 0. Ignore any alternative costs or additional costs (such as kicker) paid when the creature was cast.

2011-06-01 : A token has a mana value of 0, unless it is copying something else.

2011-06-01 : As you cast a spell or activate an activated ability with one or more Phyrexian mana symbols in its cost, you choose how to pay for each Phyrexian mana symbol at the same time you would choose modes or choose a value for X.

2011-06-01 : If a creature is copying something else, its mana value is the mana value of whatever it’s copying.

2011-06-01 : If you’re at 1 life or less, you can’t pay 2 life.

2011-06-01 : Phyrexian mana is not a new color. Players can’t add Phyrexian mana to their mana pools.

2011-06-01 : To calculate the mana value of a card with Phyrexian mana symbols in its cost, count each Phyrexian mana symbol as 1.