Cosmon Lumps and Horizonless Black Holes
  We investigate non-linear, spherically symmetric solutions to the coupled system of a quintessence field and Einstein gravity. In the presence of a scalar potential, we find regular solutions that to an outside observer very closely resemble Schwarzschild black holes. However, these cosmon lumps have neither a horizon nor a central singularity. A stability analysis reveals that our static solutions are dynamically unstable. It remains an open question whether analogous stable solutions exist. 
Timm Krueger (Uni Heidelberg), Matthias Neubert (Uni Mainz), and   Christof Wetterich (Uni Heidelberg)