Halo of Flies (5e Equipment)
From D&D Wiki
Wondrous item, rare (requires attunement)
A iron band with a pair of pretty flies perched on it, designed to be worn on the head. WHen activated by saying its command word, both flies animate and behave as normal. The flies share a pool of 20 hit points, as whichever one is less damaged will intercept attacks. When not active, the halo magically repairs the flies, causing them to regain 2d4 hit points per hour, or become fully healed when you complete a long rest.