World Key

World Key is an item in Plants vs. Zombies 2 that allows the player to unlock another world. The player can get one after beating the Gargantuar level in any world (Day 8 in the first four worlds, Night 10 in Dark Ages, and Day 16 in Big Wave Beach, Frostbite Caves, and Lost City). They were added in the 1.7 update, replacing Stars as the means of unlocking other worlds.

In the Chinese version, a World Key can be obtained by either beating the last Day in the first three worlds, or by beating the level before the first boss level in the rest (Day 14 in Kung-Fu World, and Day 29 in Far Future, Dark Ages, and Big Wave Beach).

Additionally, a free World Key was given out to all players during the Birthdayz update. This key was won for all players by Youtuber ZackScottGames when he had completed a Pinata Party challenge set by the Popcap team.

Usage
It can be used to unlock any world, according to the description. Therefore the player can go to any world in any order.

Trivia

 * The player can only get more World Keys if the player decides to purchase a world instead of using a World Key.
 * Each Gargantuar statue that is present in each area holds a World Key.
 * The advertisement for World Keys claim that the player will find Gargantuars in Day 8 of each world. However, this is not true in Dark Ages, Big Wave Beach, Frostbite Caves, and Lost City.
 * The Chinese version of Plants vs. Zombies 2 contains both Stars and World Keys, the former being used to obtain plants.
 * In earlier versions there was a glitch in which the player could randomly receive a large number of World Keys. This was fixed in a later update.