Tsukumogami are household objects such as tools, containers, and instruments that have become inhabited by spirits after existing for 100 years. The spirits cause the objects to mutate so that they gain body parts. In order to prevent objects from becoming tsukumogami, people throw them away before they are one hundred years old. However, objects that are 99 years old when they are thrown away will get angry and become yōkai in a manner independent from the passage of time so that they can cause mischief.

Tsukumogami are generally harmless. Usually, they do little more than play pranks on people. However, they can and will get very angry at wasteful people or anyone who throws objects away thoughtlessly. To prevent tsukumogami from seeking revenge, people will sometimes perform ceremonies to console broken and unusable items.

To this day, ceremonies are still held to appease old objects, especially dolls that are no longer used by their owners. Even plush toys of popular characters are used in these ceremonies now. People pray for the toys and thank them for bringing their owners happiness throughout the years. Sometimes, the dolls are burned, but the main purpose of these ceremonies is to drive any spirits out of the old toys and to bid them farewell.

FUN FACT: It is said that tsukumogami avoid electrical energy. As such, objects that rely on electricity to function cannot become tsukumogami.

Examples in various media:

Klefki (Pokémon) Other Pokémon that are tsukumogami include Banette (a doll), Litwick (a candle), and Honedge (a sword), although there are many others.

Kozo (Rosario + Vampire)

Ittan-Momen (GeGeGe no Kitaro)