Animal Crossing: Wild World

Animal Crossing: Wild World is the DS entry of the Animal Crossing franchise.

Seeds
While referred to as "seeds", the internal names for these items are usually garbled characters. They are not unused per se, as the game uses them internally when creating the town layout. However, they are normally not obtainable outside of Action Replay cheats, and for good reason.

When dropped from the inventory, they usually spawn a landscape feature: a tree, a house, a structure...and even townspeople, depending on the nature of the seed. You need to enter then exit a house to see the changes, which can't be reversed once saved.

While used by many people just to customize their own town layout, some sociopaths use them during Wi-Fi visits in other players' towns to create game-breaking layouts that may trap players irreversibly...or worse, cause the game to crash by overloading the system and rendering the game useless if it crashes on the title screen (as the Erase File option can't be accessed).

Other Items
Many regular but unobtainable items are also present.
 * Paint Can: Nook does sell these, but the paint goes straight to your roof without ever touching your inventory.
 * Beehive (later used in Animal Crossing: New Leaf)
 * Sold Out Sign
 * Four-Leaf Clover: Under Special Items. Your avatar can't wear it. (later used in Animal Crossing: New Leaf)
 * Cardboard Boxes: Come in sets of 2, 4, and 5. While being unused items, their graphics are used for neighbors moving in or out.
 * Big Rug1: Tom Nook's unused catalog version of the Exotic Wall.
 * Big Rug2: Tom Nook's unused catalog version of the Exotic Rug.
 * Honey Comb: Uses incorrectly the leaf graphics when you are inside your house, but normal graphics outside.
 * Invisible Chair: Two, in fact.

There are also four unused flooring and wallpaper sets for Nook's Cranny, Nook 'N' Go, Nookway, and Nookington's upstairs.

Crash Debugger
This game has a crash debugger triggered similarly to the one in The Legend of Zelda: Ocarina of Time. This one is a bit less technical and more informative, but a lot less in-depth.

To access the crash dump screen, first crash the game. Then, hold L + R + A + Left, let go, hold Down + B, let go, and finally hold Start + Select. This screen also exists in Super Mario 64 DS and New Super Mario Bros.

Build Date
Present in the file data/BUILDTIME.