Thrand was thought to be a werewolf

and ein-hamr, adj. ‘one-shaped,’ as equivalent in the phrase eigi e., ‘not single-shaped,’ a werewolf; it is also used with berserkr, q. v.; sem háttr er þeirra manna sem eigi eru einhamir … er af þeim gengr berserks-gangrinn, Eb. 136; Þrándr var kallaðr eigi e. ( Thrand was thought to be a werewolf), meðan hann var heiðinn, en þá tók af flestum tröllskap er skírðir vóru, 306; þykkir sem hann hati eigi síðan dyggilega e. verit, Fb. i. 260; því at þú ert eigi e., Ísl. ii. 29: without a preceding eigi (less correctly), at hann hafi sterkastr maðr verit … sá er e. hefir verit, i. e. of those who were not berserkers, Fb. i. 524, Fas. ii. 261; cp. hamr, hamramr, hamremi, hamask, etc.