Endrek Sahr, Master Breeder

The self-destruct clause is the entire design, and it is the rarest kind of token engine: one tuned to outpace its own owner. Cast a fat creature and you get a pile of Thrulls scaled to its mana value, which is exactly how you cross the seven-Thrull line and lose the engine that built them. So the incentives fight each other. The card wants you to cast big creatures for the biggest token payouts, but the bigger the creature, the faster the army that buries it. The interesting builds treat the sacrifice not as a tax but as a feature: a sacrifice outlet that eats Thrulls keeps Endrek alive indefinitely and turns each creature spell into a renewable stream of fodder, while a token doubler or a well-timed sweeper can resolve the whole thing into one explosive turn before the count comes due. It is a payoff that asks you to manage your own success, a rare design where the failure state triggers on overperformance rather than under it. The Thrull flavor anchors it to an old line of black creatures bred and discarded as resources, and the mechanic reads as a literal version of that: a breeder whose creations eventually overwhelm him. Most token generators reward you for going wide without limit; this one hands you the same incentive and then sets a clock on it, which is a sharper deckbuilding question than raw token output usually poses.