NetHack 3.0.0 was the first version to implement unique artifacts (so no more multiple Snickersnees), and featured several new artifacts, among them the lucern hammers named Thunderfist and Ogresmasher. It seems that the DevTeam forgot that a "lucern hammer" is a polearm, not to be swung as a mallet, but to be thrust at a distant enemy; it was perhaps an error to choose "lucern hammer" as the base type for both weapons. In NetHack 3.0.3, the DevTeam added a new weapon type, the war hammer, switched Thunderfist and Ogresmasher to the new type, and renamed Thunderfist to Mjollnir.
We are not sure of the origin of the name "Thunderfist", but it appears in multiple computer games of the fantasy genre; the name tends to have association with both dwarves and fighting. Angband has an artifact, the Two-Handed Flail 'Thunderfist'.
Dudley's dungeon Edit
The webcomic inserts us into the old Norse tale of the two dwarves Eitri and Brokk, who have forged "a mighty hammer" to give to the god Thor. But now, Eitri and Brokk are "specialists in polearms".
- "Then he (Brokk) gave the hammer (Mjollnir) to Thor, and said that Thor might smite as hard as he desired, whatsoever might be before him, and the hammer would not fail; and if he threw it at anything, it would never miss, and never fly so far as not to return to his hand; and if be desired, he might keep it in his sark, it was so small; but indeed it was a flaw in the hammer that the fore-haft was somewhat short."
Did Thor, desiring an unbreakable hammer, believe that the best choice would be to swing a polearm for the pounding, not to thrust a polearm for the poking? Did Thor, wanting the thrown weapon to arc and return, design it so that he would have to catch the sharp end of a Pole? Did Thor, intending a small and compact design, choose to include a stick long enough to reach a monster being two squares away? If you recall the familiar image of Thor and his hammer, and substitute his hammer with a lucern hammer, then Mjollnir the polearm seems impractical to Mjollnir's legendary capabilities.
Dudley, learning that Mjollnir is not a hammer but a polearm, would only respond in surprise: "What was Thor thinking!?"