Foreur de moelle (Pith Driller)
Foreur de moelle 

Quand le Foreur de moelle arrive sur le champ de bataille, mettez un marqueur -1/-1 sur la créature ciblée.
Texte de règles (Oracle, anglais)
When this creature enters, put a -1/-1 counter on target creature.
Après avoir foré la croûte de Mirrodin, il porta son attention sur les habitants de la surface.
Légalité
Précisions de règles (en anglais)
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.
2011-06-01
Pith Driller's ability is mandatory. If it's the only creature on the battlefield when it enters, Pith Driller's ability will target itself.