Fragmentos de médula (Marrow Shards)
Fragmentos de médula 
Los Fragmentos de médula hacen 1 punto de daño a cada criatura atacante.
Texto de reglas (Oracle, inglés)
Marrow Shards deals 1 damage to each attacking creature.
"Somos una única entidad. Los disidentes deben ser incorporados a la Ortodoxia." —Elesh Norn, Gran Cenobita
Legalidad
Aclaraciones de reglas (en inglés)
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
To calculate the mana value of a card with Phyrexian mana symbols in its cost, count each Phyrexian mana symbol as 1.
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 produce Phyrexian mana.