What is the name of the final boss zombie in the original game?

The final boss zombie in the original Plants vs. Zombies is Dr. Zomboss. He is the leader of the zombie invasion and appears in the climactic battle at the end of Adventure Mode.

Dr. Zomboss does not fight as a normal walking zombie. He operates the enormous Zombot, a machine that attacks the lawn by stomping plants, launching vehicles, and using fire or ice-based attacks. The player must damage the machine while managing waves of zombies and choosing plants that can survive its attacks.

Zomboss is sometimes confused with the Zombot because the two appear together in the final battle. The Zombot is the machine; Dr. Zomboss is the character controlling it. Gargantuar is also a major late-game threat, but it is a powerful standard zombie rather than the original game's final boss. The character is also known as Dr. Edgar Zomboss in later franchise material.