Mishra's Factory

The original man-land, and the template every animated land since has measured itself against. The structural trick is the three-ability stack: it taps for colorless like any utility land, it pays one mana to become a 2/2 Assembly-Worker that is still a land (so it dodges sorcery-speed creature removal when left untapped, and shrugs off the sweepers that only catch creatures), and it taps to hand an Assembly-Worker +1/+1. That third ability is the design flourish that makes the card more than a beater, and the target clause is wider than it looks: it can pump any Assembly-Worker, including itself. Animate it to block, then tap it to grow into a 3/3 and eat the attacker, all at instant speed. The cost split keeps the package honest: animation costs one mana, the pump costs the tap, so a single Factory cannot both swing and grow on the same turn. With two in play, one taps to feed the other while the second attacks as a 3/3. Mishra's Factory established the rate that later man-lands have been priced against ever since: Mutavault widened the creature type, Treetop Village pushed the body to a 3/3 trample for an extra mana, Inkmoth Nexus traded toughness for infect and flying. None reopened the self-pumping Assembly-Worker clause; that tribal hook stayed unique to the original. It remains the early proof that a colorless utility land could threaten lethal damage from the manabase itself.