Eitr

Eitr is a mythical substance in Norse mythology. This liquid substance is the origin of all living things, the first giant Ymir was conceived from eitr. The substance is supposed to be very poisonous and is also produced by Jörmungandr (the Midgard serpent) and other serpents.

Etymology
The word eitr exists in most North Germanic languages (all derived from the Old Norse language) in Icelandic eitur, in Danish edder, in Swedish etter. Cognates also exist in Dutch ether, in German Eiter (lit. pus),in Old Saxon ĕttar, in Old English ăttor. The meaning of the word is very broad: poisonous, evil, bad, angry, sinister etc.

Eitr is present in sections of the video game Tomb Raider Underworld, which uses eitr frequently as an obstacle to avoid. During the course of the game, the eitr is shown to produce undead thralls as guardians, assumed to be victims who had fallen or been thrown into the eitr in the past. The villain of the game, Jacqueline Natla, is defeated when she is thrown into the poisonous eitr at the game's conclusion. Natla, unlike the others who had fallen in, survives with her mind intact, but is later drowned in eitr in the conclusion of Lara's Shadow. The Eitr Stone has the power to turn plain water into eitr.

Lara's Journal Entry
''In Norse myth, eitr was an elixir that bestowed eternal life to the gods, but paradoxically it was a poison that came from serpents, like the Midgard Serpent. This is similar to the Hindu concept of amrita, or ambrosia to the Greeks. Only the Norse came the closest to the literal truth: that the substance was indeed a poison, and in fact only gave the appearance of eternal life in the animation of corpses.''