Dismember

Instant

( can be paid with either or 2 life.)
Target creature gets -5/-5 until end of turn.

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:
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 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.