Eubacteria, The True Bacteria

Haste, Double Strike, Vigilance
At the beginning of your upkeep, deal {x} damage
to any target.
When Eubacteria dies, create 2 1/1 Virus tokens
with "At the beginning of your upkeep, deal 1
damage to any target."
The Infection spread rapidly, consuming everything in
it's path until there was nothing left.