Zarosian staff

The Zarosian staff is part of the Zarosian armour set, and was released along with the God Wars Dungeon expansion update. It requires 70 Magic to wear. It is a possible drop from Lord Shadowcore and his bodyguards in the God Wars Dungeon.

It has a special attack called Dark possession, which temporarily causes your opponent to have a 25% chance of inflicting damage on themselves rather than you. This effect lasts for 10 seconds. The attack uses 100% of the Special attack bar, and drains 10 of your prayer points.

Its set effect, which occurs when wearing the full Zarosian set, slightly boosts your damage and accuracy when using Magic depending on how close you are to death; the lower your LP, the bigger the boost is.

Trivia

 * The Zarosian staff was once called the "Zaros staff", but was re-named to avoid confusion with the Zaros rune armour from Treasure Trails.