Alex Mercer, Virus Dominus

Deathtouch, Haste, Lifelink, Undying
As an additional casting cost, you may sacrifice any number of Infected creatures. For every 3 creatures sacrificed this way, this creature gains these abilities, in order: (trample and reach, first strike, vigilance.)
All other Evolved Infected creatures you control gain +2/+2 and haste.
Partner