We present results from new deformation experiments and a dislocation creep flow law for synthetic ilmenite. The flow law predicts an effective viscosity more than three orders of magnitude lower than dry olivine at mantle stresses and temperatures. Using the flow law, we predict that lunar ilmenite-bearing cumulates (IBC) will be weakened by the presence of low viscosity ilmenite. Dense, low viscosity IBC are expected to flow into the lunar interior by a process known as cumulate mantle overturn. Low viscosity IBC that sink to the core-mantle boundary may be dynamically stable with respect to upwelling. A hot, stable layer of IBC surrounding the lunar core would suppress the development of a core dynamo. A layer of partially molten IBC can also explain the inferred zone of seismic attenuation around the lunar core, as well as a low viscosity layer suggested by tidal dissipation.