The Papal Bull (Warhammer +2)

This gigantic warhammer is forged of pure mithril. Its head and handle are immaculate despite obvious years of use.
The Papal Bull seeks out its targets with righteous indignation. If you miss with an attack, add +1 to your next to-hit roll. This effect is cumulative until you score a hit, at which point all to-hit bonuses reset back to zero.