Quantum geons
  We describe solutions of the Klein-Gordon equation which are spherically symmetric and localized, and may be regarded as massive particles without charge or spin. The proposed model, which is based on the action for a complex scalar field minimally coupled to the electromagnetic and gravitational fields, contains no adjustable parameters and predicts five particle species with masses of the order of the Planck mass. These particles appear to be candidates for dark matter. 
Richard A. Sones