From GameWatcher: “Dauntless plays host to a staggering number of varied resources and items to craft and re-craft into one another, some of the most important of which are reagents. These Behemoth drops are used by Aethersmits to craft weapons, armour, and consumables, and Shock Tooth is one of ’em.
Dauntless Shock Tooth is a particular type of common reagent found on the Nayzaga Behemoth, and let us tell you – they’re not an easy kill by any stretch.”
Source: N4G PC Dauntless Shock Tooth – How to get Shocktooth?