Zoo Tycoon 2: Extinct Animals Easter Egg - Killer Penguins and Quagga

The unlockable "killer penguin" is a reference to the original Zoo Tycoon game, where penguins could kill any herbivore, although Extinct Animals version can kill any animal. The fact that the penguin is from Madagascar may be a reference to the agent penguins from the film Madagascar. Sometimes the killer penguin will appear in the research lab, replacing the scientist. The killer penguin's Zoopedia entry states that "If someone offers you a penguin for free, you should say no". In challenge mode, occasionally a message comes and states that a zoologist has found a penguin wandering the Arctic, and offers it to the player's zoo for free. The penguin is really a killer. The animal can be unlocked by achieving a score between 10% and 50% in the animal creation minigame.