"The zombie upgrade increases the speed of the Zombies."
Zombies are an undead unit associated with the Necropolis faction as the second tier unit in the video game Heroes of Might and Magic II: The Restoration of Erathia and its expansion, The Price of Loyalty. They can be recruited by a player in possession of a Necromancer town by upgrading a graveyard. Like all other undead units in the game, they are immune to any and all mind-affecting spells, as well as Bless and Curse, as well as always possessing neutral morale.
When compared to regular Zombies, Mutant Zombies are afforded slightly higher hit points as well as a much higher speed rating, allowing it to actually take the battle to their enemies.