However, they would die eventually, as the wounds were no less fatal, the soldiers simply did not feel them. The only known way to kill them was to behead them or otherwise damage their head, suggesting that their brain was the weak point. Additionally, if sufficiently wounded, they might eventually die over time due to loss of blood. A group of them were sent to attack the Varden while Saphira and Eragon fought Thorn and Murtagh. Roran also encountered them on his second mission. He refused the choice Nasuada offered him to become like one of them, saying that if he was not able to feel pain, then he might become careless and ignore wounds that would kill him. Nasuada had, in fact, been creating her own small contingent of soldiers with this ability, Roran's refusal may have dissuaded her from the idea, as nothing was mentioned of the idea following this.
Their most notable feature is the fact that, in spite of all the injuries they suffer, they laugh maniacally, since they know nothing can cause them hurt. This highly unnerving cackle, combined with their abilities, is said to be highly demoralizing to enemy forces. They also had a habit of playing dead, then rising up when least expected to injure or kill once more.
Following their initial creation by Galbatorix, the Laughing Dead appeared in several key battles, including the Battle of Urû'baen. After this battle, it is likely that Eragon used the Name of Names to remove the spell from any Laughing Dead that were still living, though it was never mentioned specifically.
The spell was presumed to require very little energy.