The Starving Horde
At the end of each turn, The Starving Horde's maximum health is reduced by 3. The Starving Horde gains +1 bloodthirst each time it's health is reduced this way. In addition to this, this Starving Horde gains +1/+0 each time a different friendly Starving Horde has its health reduced.
"With their numbers and strength dwindling, some Sleepers resorted to devouring even each other."
"Needless to say, this did nothing but perpetuate their blood-lust."
Essentially, by the time this card is no longer exhausted, it is a 10/12 with bloodthirst 1. Also, its maximum health is REDUCED (permanently gone), not DAMAGED. This is to prevent cheese with healing such as Tribal Medicine, and have given it consume 1 to make up for this a little bit (plus it fits thematically).
I'm debating on whether or not this card should be allowed as a commander, just to prevent possible cheesy combos that might arise.