Wren's Run Packmaster

The Champion mechanic was a clever sleight of hand: a creature pays for its body by tucking another creature away, then hands that creature back the moment the new one leaves the battlefield. Most champions simply upgraded a small thing into a bigger thing, but this one turns the swap into a production line. The exiled Elf is held hostage; in exchange you get a 5/5 that prints 2/2 Wolves at will, and every one of those Wolves carries deathtouch. That keyword grant is what warps combat math. Deathtouch on a token factory means each Wolf trades up with anything on the board, no matter how large, so the activated ability is not just a mana sink for a growing army but a steady supply of disposable removal that also blocks. The Champion text does the balancing work: kill the Packmaster and the championed Elf returns, which sounds like insurance but actually means the deathtouch and the token spigot vanish together, so a well-timed removal spell deletes the whole engine rather than a single body. It rewards committing an Elf you were happy to get back later, and punishes overextending into a board wipe. The token-and-anthem shape, a creature that makes bodies and then makes those bodies dangerous, has been revisited many times since, but few packed the recursion, the army, and the keyword grant into one four-mana frame.