Eternal Taskmaster

The recursion is bolted onto the attack step, and that placement is doing more than it looks. Gravedigger and its many cousins hand you a creature the moment they hit the battlefield; this pays the cost only after you've committed to combat, whether or not the body gets through. The trigger fires on attack, so a blocker cannot switch off the engine, only the death of the Taskmaster can. Every returned creature costs three mana on top of the swing, which turns keeping a two-power zombie alive across turns into the price of admission rather than cashing it in once. The enters-tapped clause pushes the whole clock back a turn, the tax for stapling repeatable graveyard retrieval to a two-drop instead of a one-shot enter-the-battlefield effect. In exchange you get a bridge that never closes: no exile clause, no counter capping the loop, just a recurring path from graveyard back to hand for as long as the creature attacks. That makes it a natural partner for anything that wants to die cheaply and be recast, since it keeps refilling the pile it draws from, and note the card comes back to hand, not to the battlefield: you still pay to redeploy it. It is a grind piece dressed as an attacker, its aggressive attack trigger stapled to the defensive work of winning a long attrition game, both jobs crammed into the same small black body.