Wroshyr lice were small parasites found on Kashyyyk that lived on wroshyr trees and inflicted Wookiees. They were used to make Wroshyr lice syrup. It is said that when a female Wookiee drops a Wroshyr louse on a male Wookiee it is a gesture of affection. The female Wookiee is then supposed to groom the fur of the male hit with the louse as an apology. Mallatobuck attempted to drop a louse on Chewbacca, however, he was pushed out of the way by another Wookiee right before the louse hit.