Harbinger of the Source

Devoid
Whenever Harbinger of the Source deals damage to a player, create a 0/1 Eldrazi Spawn with "Sacrifice this creature: Add {c} to your mana
pool."
Lieutenant -- As long as you control your commander, Harbinger of the Source has Trample and Menace.
No one knew what the being was saying, only that it was ominous.