  Recently, a spin one half matter field with mass dimension one was
discovered, called Elko spinors. The present work shows how to introduce these
fields into a curved spacetime by the standard covariantisation scheme. After
formulating the coupled Einstein-Elko field equations, the spacetime is assumed
to be homogeneous and isotropic in order to simplify the resulting field
equations. Analytical ghost Elko solutions are constructed which have vanishing
energy-momentum tensor without and with cosmological constant. The cosmological
Elko theory is finally related to the standard scalar field theory with self
interaction that gives rise to inflation and it is pointed out that the Elko
spinors are not only prime dark matter candidates but also prime candidates for
inflation.
