The halo star Feige 86 was considered in the 1960's and 1970's a solar metallicity chemically peculiar, He-weak B type star. Margherita Hack was the first to study its UV spectrum acquired with the IUE satellite. Later studies of this star by Hack and collaborators suggested that, in spite of the fact its iron abundance is slightly above solar, the star is a Pop II Horizontal Branch star. The high abundance of Fe and other iron-peak elements is due to an atmospheric phenomenon, probably related to diffusion, that increases their abundance above the intrinsic abundance of the star. The parallax measured by the Gaia satellite confirms this hypothesis and makes this bright star an ideal prototype of stars in this evolutionary state.