Rocky Helmet is a great item for Skarmory, and might even be optimal (I've been so impressed that I dropped Leftovers for it). Rocky Helmet ruins Mega Kangaskhan's day and does a number on all the physical Pokemon that Skarmory routinely switches in to (locked into Outrage? Trololol). It damages Aegislash (punishing those without Leftovers) and charges Rapid Spinners 1/6 of their HP to clear hazards as well.