Ahrim's staff

Ahrim's staff is a one-handed magic weapon that is part of Ahrim the Blighted's set. To wield Ahrim's staff, the player must have 70 Magic and 70 Attack.

Being part of Ahrim's set, if the staff is wielded along with all of the other pieces of equipment in the set the player receives a special effect: successful attacks have a 25% chance of lowering the opponent's Strength by five levels. This is cumulative with other effects that lower strength, namely the spell Enfeeble.

Wearing an amulet of the damned in addition to the entire set provides an extra effect: the staff gains the ability to autocast Ancient Magicks, and combat spells have a 25% chance of dealing 30% extra damage. However, this amulet cannot be used concurrently with the damage-boosting occult necklace.

Trivia

 * Prior to an update on 16 November 2017, Ahrim's staff was a two-handed staff, and did not have a 5% magic damage bonus.