Here are a few others, its the prismatic blessing buff, fyi.
Non lvl 70Characters are incapable of dying in Dragon Isles - Support / Bug Report - World of Warcraft Forums (blizzard.com)
10-70 Leveling Guide in TWW - Community / General Discussion - World of Warcraft Forums (blizzard.com)
My Warlock has become immortal and cannot die - Support / Bug Report - World of Warcraft Forums (blizzard.com)