By halves (autophagia)
Authors' Note: Goose bumps or goose pimples are a common transient physiological change produced by stimulation of the skin's small and widely distributed arrector pili, tiny muscles at the base of each hair follicle. Their appearance may be provoked by physical conditions (such as a cold environment) or emotional factors, including embarassment, a sexual turn-on, or fear. The latter, accompanied by profound anxiety (the heebie-jeebies), and "hair standing on end" (piloerection or horripilation) is a reaction scaled down from that found in the animal kingdom, e.g. porcupines throwing their quills to put off predators.
Heebie-jeebies is gramatically another of those appealing (re) duplications, like helter-skelter and hocus-pocus, and represents a topic appropriate for discussion on Hallowe'en.