The quanta of phantom dark energy models are negative energy particles, whose maximum magnitude of energy |E| must be less than a cutoff \(\varLambda \lesssim 20\)  MeV. They are produced by spontaneous decay of the vacuum into phantoms plus normal particles. I review general cosmological constraints that have been derived from the effects of such phantom fluid production, and a possible application: the generation of boosted dark matter or radiation that could be directly detected. Recent excess events from the DAMIC experiment can be well-fit by such processes.