Berserker bones are dropped by Wilderness Berserkers. The bones that gives 100 Prayer experience directly and after it's buried it will burn. While burning the player will receive 10 Prayer experience per tick for 6 seconds, resulting in up to 100 additional Prayer experience. This only happens when bones are not used on a altar or are cremated. In practice, this means that when the bones are buried outside of Wilderness, they provide a total of 200 Prayer experience.