Oddest Cause of Death Ever?

Around 875 there was a man by the name of Sigurd I, also known as Sigurd Riki (Sigurd the Mighty) who was the earl of Orkney.  He was a brother to Ragnald I and a direct descendant of one of several lines of Scandinavian kings.  Ragnald initially was earl (jarl) of Orkney, but chronicles suggest he had little interest in administration and more in seafaring and warfare.  He gave the title and the responsibility to Sigurd.

via Pinterest.  Depiction is from a 6th century viking helmet

Sigurd was ambitious and wanted to establish his own kingdom.  He teamed up with a cousin--the descendant of one of his ancestral uncles--and began to conquer northern Scotland.  These conquests became the  material of many Norse sagas, all of which portray Sigurd and his cousin Thorstein the Red, as two of the mightiest warriors of their day.  They conquered the Picts of northern Britain, which resulted in the border of their combined kingdoms extending considerably south, with Sigurd possibly also laying claim to the northern Hebrides.

The Scottish kings were apparently too busy sorting out their own affairs in the south.  Attempts to defend against the invaders were left to the earls of the Picts and Scots.  One such earl was Maelbrigte, who was possibly the earl of Moray (and therefore an ancestor of Macbeth).  He refused to negotiate terms with Sigurd, who flew into a rage  and killed Maelbrigte.  He hung Maelbrigte's head from his saddle as a trophy.  Over the course of riding, however, the teeth from the severed head scraped Sigurd's leg.  He developed septicemia and died, thus becoming the only ruler known to have been killed by being bitten by a dead enemy.