Planetary nebulae have been a addition to the zoo of X-ray-emitting
sources. Here I present results on a the very particular class of
born-again planetary nebulae, those whose central star has experienced
a helium shell flash during the lifetime of the planetary nebula.
The interaction of the fast stellar wind of the central star with
hydrogen-poor material ejected during the born-again episode provides
a unique case to study ablation, mass-loading winds, and charge-exchange
processes.