  Higher spin gravity is an interesting toy model of stringy geometry.
Particularly intriguing is the presence of higher spin gauge transformations
that redefine notions of invariance in gravity: the existence of event horizons
and singularities in the metric become gauge dependent. In previous work,
solutions of spin-3 gravity in the SL(3,R) x SL(3,R) Chern-Simons formulation
were found, and were proposed to play the role of black holes. However, in the
gauge employed there, the spacetime metric describes a traversable wormhole
connecting two asymptotic regions, rather than a black hole. In this paper, we
show explicitly that under a higher spin gauge transformation these solutions
can be transformed to describe black holes with manifestly smooth event
horizons, thereby changing the spacetime causal structure. A related aspect is
that the Chern-Simons theory admits two distinct AdS_3 vacua with different
asymptotic W-algebra symmetries and central charges. We show that these vacua
are connected by an explicit, Lorentz symmetry-breaking RG flow, of which our
solutions represent finite temperature generalizations. These features will be
present in any SL(N,R) x SL(N,R) Chern-Simons theory of higher spins.
