William Birkin, G-Virus Form 1

Vigilance, Rampage 1
Other Human creatures you control get +1/+0
and Rampage 1.
{t}: Add {w}{b} to your mana pool.
When William Birkin, G-Virus Form 1 dies, you may search your hand, graveyard, or library for William Birkin, G-Virus Form 2 and put it onto the battlefield tapped without paying it's mana cost.