Screaming Seahawk
The self-fetching toolbox before the formula got cheap, back when the search pulled a single twin rather than a fistful. The design idea is guaranteed redundancy out of one slot: each casting nets a body on the battlefield and a fresh copy in hand, so in raw card count it pulls ahead by one while keeping the next iteration loaded. The deck that wants a flier every turn, or bodies to discard, sacrifice, or flicker, gets a reliable trickle without committing more than a single name to the list. The cost is the brake. Five mana whose only payoff is fetching another five-mana flier is a glacial engine by any honest measure, and the 2/2 offers nothing in combat the price would not otherwise demand. Squadron Hawk later compressed the same shape into two mana and three fetches, which is why the Seahawk reads as the prototype the design was eventually tuned past: the bones are identical, the rate is brutal. The body is the proof of concept, expensive enough that the chain only earns its keep where the fliers are working beyond the red zone, feeding a graveyard or a sacrifice outlet rather than just attacking.

