A Lazarus Pit was a mysterious fluid-filled pit in the earth that would regenerate and even revive the dead or dying and kill the healthy, though with some side effects, most famously bouts of insanity, though other long-term effects include dependency. Also, it was not a permanent solution to escape mortality, as over time they lost their effectiveness.
Ra's al Ghul lived for over 600 years through the use of Lazarus Pits. In Batman Beyond's future, the process of using the Lazarus Pits has become much safer and although the pit's restorative powers make Bruce's body more youthful, because of his age in the series he would require multiple doses for the effects to be long-lasting; that is why Bruce reverts back to his elderly state within about a week after using the pit.
Sightings and references
- "The Demon Reborn" (Mentioned Only)