Lethal Doggler is an Earth Imperial Beast that terrorized the Underground Empire Tube in the past and a posthumous antagonist in Hikari Sentai Maskman.
Born from a pool of dark energy, the Lethal Doggler saw itself as a superior being to other lifeforms and attempted to revolt against the Igam Family to usurp them as ruler of the underground. In response, the Tube forces waged a war against the beast and defeated it. With the beast seemingly dead, the Tube built a pyramid-shaped tomb to encase its body and set up Haniwa Doggler to guard it.
However, not fully dead but extremely weakened, the Lethal Doggler escaped the tomb and crawled outside, where it used the last of its energy to lay a single egg. The egg hatched into Lethal Doggler II, which consumed its parent's body to become stronger. Within the next 300 years, the child took up the identity of "Emperor Zeba" and ousted the Igam Family from power, taking control of the Tube kingdom transforming it into a brutal and militaristic dictatorship. Because of Lethal Doggler's infamy however, Zeba kept his true origins as Lethal Doggler's descendant a secret.
Seeking the power to defeat the Maskmen, Prince Igam attempted to harness the power of the pool Lethal Doggler was birthed from. However, Igam inadvertently awakens Lethal Doggler's spirit, which possesses Godai Doggler and goes on a rampage. Lethal Doggler was ultimately defeated for good when the Maskmen destroy it and the Earth Imperial Beast it was possessing.