"Mobile Phone Beast Telefang") is a series of role-playing video games (RPGs) developed by Natsume Co., Ltd. and published by Smilesoft.

[4][5][3] In the games, the player contacts various creatures using a mobile phone-like device in order to get them to battle the foes they will encounter.

The name of the series derives from keitai (携帯), the Japanese term for mobile phone, as making phone calls to the creatures is an integral part of the games, and fang, to symbolize the various beasts involved.

The games are played from a third-person, top-down perspective, with the player taking the role of the games' young protagonist and main T-Fanger: Shigeki in Keitai Denjū Telefang and Kyō in Keitai Denjū Telefang 2.

The type of habitat a Denjū lives in determines how weak it is to attacks from Denjū from other habitats; there is a vulnerability chain that goes from Mountain to Sky, from Sky to Forest, from Forest to Aquatic, from Aquatic to Desert, from Desert to Grassland and, finally, from Grassland to Mountain.

However, this was slightly changed in Keitai Denjū Telefang 2, where Denjū's habitat types are defensive, and attacks are of separate offensive types: Normal, Flame, Thunder, Water, Wind, Rock and Machine.

This arrangement makes Denjū a bit more versatile, as they may carry moves that would be effective against opponents they would normally have trouble against.

The battles are not strictly turn-based; the Speed stat of a Denjū determines how many turns it can take and when.

In Keitai Denjū Telefang 2, instead of having to wait for a Denma attack to charge, its use is limited by a DP meter.

Such items range from simple objects like pencils and batteries to flamethrowers, computers, cranes and shuriken.

The games follow the story of Kyō, a blue-haired 10-year-old T-Fanger who travels to the Denjū world to look for his missing father.

First released as a monthly feature in the Comic BonBon magazine, the manga's issues were later reprinted as a set of three tankōbon, or volumes.

A manga was also serialized by Kodansha for Keitai Denjū Telefang 2; however, it was featured only in the Comic BonBon magazine and was never reprinted.