This special New Rule card only works in your Zombie Fluxx deck. It is in current printings (Version 1.2 and newer) of Zombie Fluxx, but older versions do not contain it.
It says, "The player with the most Zombies is called the Zombie Boss, and keeps this title until someone else has more Zombies. The Zombie Boss: Draws 1 extra card each turn, is ignored during the Action Eaten by Zombies and wins if the game ends because of the Zombie Victory Ungoal." more info
This card was released as part of a bundle with a small or large wooden box with "Zombie Fluxx" burned into the lid. We have since discontinued the boxes, but this promo card was too great to discontinue!