Avaloth is a fictional monster created by Richard F. Searight for his short story "The Sealed Casket". It is also mentioned alongside Cthulhu and Tsathoggua in "The Warder of Knowledge".
Description[]
Avaloth is an invisible creature with slender tentacles, strong enough to break every bone of a man's body, and drain its victims of blood. It also has the ability to absorb heat and drastically lower the temperature of its environment. Conversely, a great source of heat, such as fire, might destroy it.
In the "Elder Time", Avaloth used its abilities to generate ice and snow and threatened to cover the entire Earth in an ice sheet, but was imprisoned inside a sealed casket by the great wizard Om Oris before it could do so. After its imprisonment, the ice-covered regions returned to their previous verdant state. Many ages later, Avaloth was released by Wesson Clark and killed him, but was itself destroyed when Clark's house was engulfed in flames. (CIRCLE: "The Sealed Casket")
Behind the Mythos[]
Avaloth is similar to the Star Vampire from Robert Bloch's "The Shambler from the Stars". Both are invisible monsters who kill victims in the exact same manner: crushing the body to death with their tentacles while draining all the victim's blood. Coincidentally, both stories were first published in 1935 in the magazine Weird Tales, and both end in a house fire.
On a different note, Avaloth is also similar to Aphoom-Zhah, from Lin Carter's "The Acolyte of the Flame", as both entities have been responsible for creating a giant ice sheet that spread southwards, covering vast areas of formerly green land with ice.
In "Wrath of the Wind-Walker", by James Ambuehl and Robert M. Price, it is suggested that Avaloth is just another name for Ithaqua, and possibly Aphoom-Zhah as well.