Ratatoskr

In Norse mythology, Ratatoskr (Old Norse, generally considered to mean "drill-tooth" or "bore-tooth") is a squirrel who runs up and down the world tree Yggdrasill to carry messages between the eagle perched atop Yggdrasill, and the serpent Níðhöggr, who dwells beneath one of the three roots of the tree. Ratatoskr is attested in the Poetic Edda, compiled in the 13th century from earlier traditional sources, and the Prose Edda, written in the 13th century by Snorri Sturluson.

Etymology
The name Ratatoskr contains two elements: rata- and -toskr. The element toskr is generally held to mean "tusk". Guðbrandur Vigfússon theorized that the rati- element means "the traveller". He says that the name of the legendary drill Rati may feature the same term. According to Vigfússon, Ratatoskr means "tusk the traveller" or "the climber tusk."

Sophus Bugge theorized that the name Ratatoskr is a loanword from Old English meaning "Rat-tooth." Bugge's basis hinges on the fact that the -toskr element of the compound does not appear anywhere else in Old Norse. Bugge proposed that the -toskr element is a reformation of the Old English word tūsc (Old Frisian tusk) and, in turn, that the element Rata- represents Old English ræt ("rat").

According to Albert Sturtevant, "[as] far as the element Rata- is concerned, Bugge's hypothesis has no valid foundation in view of the fact that the [Old Norse] word Rata (gen. form of Rati*) is used in Háv[amál] (106, 1) to signify the instrument which Odin employed for boring his way through the rocks in quest of the poet's mead [...]" and that "Rati* must then be considered a native [Old Norse] word meaning "The Borer, Gnawer" [...]".

Sturtevant says that Bugge's theory regarding the element -toskr may appear to be supported by the fact that the word does not appear elsewhere in Old Norse. Sturtevant, however, disagrees. Sturtevant says that the Old Norse proper name Tunne (derived from Proto-Norse *Tunþē) refers to "a person who is characterized as having some peculiar sort of tooth" and theorizes a Proto-Germanic form of -toskr. Sturtevant concludes that "the fact that the [Old Norse] word occurs only in the name Rata-toskr is no valid evidence against this assumption, for there are many [Old Norse] hapax legomena of native origin, as is attested by the equivalents in the Mod[ern] Scandinavian dialects." Modern scholars have accepted this etymology, listing the name Ratatoskr as meaning "drill-tooth" (Jesse Byock, Andy Orchard, Rudolf Simek) or "bore-tooth" (John Lindow).

Attestations
In the Poetic Edda poem Grímnismál, the god Óðinn (disguised as Grímnir) says that Ratatoskr runs up and down Yggdrasill bringing messages between the eagle perched atop it and Níðhöggr below it: Ratatoskr is described in the Prose Edda 's Gylfaginning 's chapter 16, in which High states that

Theories
According to Rudolf Simek, "the squirrel probably only represents an embellishing detail to the mythological picture of the world-ash in Grímnismál". Hilda Ellis Davidson, describing the world tree, states the squirrel is said to gnaw at it—furthering a continual destruction and re-growth cycle, and posits the tree symbolizes ever-changing existence. John Lindow points out that Yggdrasill is described as rotting on one side and as being chewed on by four harts and Níðhöggr, and that, according to the account in Gylfaginning, it also bears verbal hostility in the fauna it supports. Lindow adds that "in the sagas, a person who helps stir up or keep feuds alive by ferrying words of malice between the participants is seldom one of high status, which may explain the assignment of this role in the mythology to a relatively insignificant animal".

Richard W. Thorington Jr. and Katie Ferrell theorize that "the role of Ratatosk probably derived from the habit of European tree squirrels (Sciurus vulgaris) to give a scolding alarm call in response to danger. It takes little imagination for you to think that the squirrel is saying nasty things about you."

In popular culture
Ratatoskr appears in the 2018 video game God of War, where he has the ability to provide the player with healing items.

He also appears as a playable character in the game Smite.

In the 2010 video game Young Thor, Ratatoskr is depicted as an ally of Hel, who serves as the game's antagonist.

Ratatoskr also appears in the 2020 video game Assassin's Creed Valhalla, where he engages the player in flyting, a poetic duel, in the mythical realm of Jötunheimr.

In the comic book series The Unbeatable Squirrel Girl, Ratatoskr is featured as a villainous female squirrel god from Asgard who wants to destroy all of humanity. She was defeated by Squirrel Girl after she teamed up with Thor and Loki. However, she later teamed up with Squirrel Girl to fight the Frost Giants.

Ratatoskr appears in the trading card game Magic: The Gathering as ‘Toski, Bearer of Secrets’; a homage to the mythical creature. The card’s effects connote their tenacity to exchange information between the many realms of Kaldheim.

Ratatoskr can be cast as the spell "Ratatoskr's Spin," as of 2019, in the video game Wizard101, where he climbs down the world tree, digging up a giant acorn and damaging all enemies with it.

In the novel Hammered, Atticus rides Ratatoskr to the top of Yggdrasill on his quest to steal the golden apples of Iðunn.