Alf the Alchemist in Wulverberg has an interesting deal for the players.
He claims that he can make a powerful concoction to create an explosive vial that he calls a Vial of Flashbang. It is used as a tactical distraction tool that can both temporarily blind and deafen a target caught in the explosion.
In order to make these he needs many samples of Glow Dust, found only in Will O' Wisps. He needs many samples so that he can make a very concentrated solution for it to work.
For every 50 units of Glow Dust brought to him, he will reward the players with 250 gold pieces and 10 of their very own Vials of Flashbang.
Will O' Wisps can be found in Krypdyr Marsh.