Halo
From Tardis Wiki, the free Doctor Who reference
Halos are rings that often are used on angels. Halos hover (or are kept up by some object) obove the head of the angel. On board the Titanic when the angel like the Host of Heaven turned against the crew they used their halos as weapons. They pulled them from spikes on their head and flung them like boomerangs. (DW: Voyage of the Damned)
