I would say it most resembles the guttural cry of a wounded animal crossed with the really annoying blaring pattern of a car alarm with just a hint of banshee for good measure.
Upon making it last the other night when my husband briefly knocked himself out by hitting his head into a door jamb, my initial thought (after 'OMG! My husband just knocked himself out by hitting his head into a door jamb!') was 'Augh, I wish that terrible sound would stop! Oh, that is coming from my head. . . I should not make that sound.'