Barrelchest is a monster that serves as the boss near the end of The Great Brain Robbery. It has two attacks: attacking you with its anchor if you are in melee range, and if it cannot reach you, it will perform an attack in which it will slam its anchor to the ground, triggering an earthquake that can inflict up to 25 damage. Protect from melee is highly advised, but due to Barrelchest's attacks deactivating and draining prayers, it is recommended to use quick-prayers to reactivate prayers swiftly. Upon defeat, Barrelchest will drop the barrelchest anchor, but it requires repairs before it can be equipped.
Due to its high offensive melee stats, it is recommended to wear armour that provides high melee defence, preferably against crushing attacks. Barrelchest also drains your defence. Lower level players are advised to use a super defence potion, have a prayer potion on standby, and high healing foods. Fast melee weapons such as the dragon dagger's special attack and the abyssal whip are effective.
Barrelchest can be fought in the Nightmare Zone after the quest is complete.