Brain

The Brain is the center of the nervous system of the human body and directs all the body's actions in most animals. It is also the favorite food of the zombies. In Versus Mode, they are the zombie faction's equivalent of sun.

Purpose
In Plants vs. Zombies, the zombies eat brains, which is why the player's house is being invaded. They also appear in the mini-game Zombiquarium, where they are used to feed Snorkel Zombies so they don't die, the I, Zombie Puzzle Mode levels where the player plants zombies who must eat the brains at the end of every lane, and as the Zombie equivalent of sun in Versus Mode. A brain is also featured in the song Zombies on Your Lawn, and is used as a pointer for the lyrics. In parts of the game, some zombies can be seen showing brains on pieces of their clothing or equipment. For example, the Zombie Bobsled Team has a brain picture on the front of the bobsled and the words "Brains or Bust" written on the side, the Dolphin Rider Zombie speedo-type outfit has a picture of a brain on it, the Snorkel Zombie has a shirt with the legend "I ♥ Brains," and the Flag Zombie carries a red flag with a picture of a brain on it, the Chinese Zombies has a take out box with brains on the side.

Additionally, a game over message in green slime saying "THE ZOMBIES ATE YOUR BRAINS!" will appear along with a loud "NOOOOOOOOOOOOOOOOOOOOOOOO!" if the zombies get inside the player's house. The player can also hear the game over noise in the Online Hacked version if the player holds the ">" button.

thumb|200px|right|The players scream when their brains get eaten

Versus Mode
The brains are given a vital role in the Xbox Live Arcade and DS versions as the Zombie's equivalent of sun. They are used to create zombies to attack the opponent's lawn and try to eat their brains. Much like sun, brains will fall from the sky anywhere in the three lanes controlled by the player who is playing as zombies, and will be produced from Zombie Gravestone at the same rate that Sunflowers produce sun.

Trivia

 * Dr. Zomboss already has his own brain, though the zombies don't seem to get attracted to it which is probably the zombies are unintelligent or because he may have hypnotized the zombies to eat humans' brains
 * May be the Zombies feared Dr. Zomboss' zombot
 * In Zombiquarium, one brain costs five sun. This is odd because in Vs. Mode, one gives five times the amount of power one costs. Of course, these are in two completely unrelated game modes.
 * The in-game brain looks like a puff of pink smoke. The brains in the game are pink, however, in real life, they are gray (this is very common in games).
 * Several zombies use pictures of brains on items they use or carry.