Skithiryx, the Blight Dragon

Flying
Infect (This creature deals damage to creatures in the
form of -1/-1 counters and to players in the form of
poison counters.)
{b}: Skithiryx, the Blight Dragon gains haste until end of turn.
{b}{b}: Regenerate Skithiryx.
"It was once a tool of the Phyrexians. Scion ensured it became their end."