  We encounter these demons on the path towards a UV complete QFT of gravity
and a horizonless replacement for black holes. The fate of the ghost is
discussed in the strong coupling version of classically-scale-invariant
quadratic gravity. Rather than a propagating ghost, the full graviton
propagator ends up with a slight acausal behavior. We then turn to the 2-2-hole
solutions appearing in a classical approximation of the gravity theory. We
present a new solution that is sourced by a relativistic gas, where a benign
timelike singularity is shrouded by a fireball. Calculating the standard
entropy gives an area law, and the entropy of a 2-2-hole can exceed that of the
same size black hole. Finally, an observational consequence of 2-2-holes takes
the form of gravitational wave echoes that can be generated by a newly formed
2-2-hole after a 2-2-hole merger. LIGO is sensitive to such a signal. We update
the evidence from our previous search with five additional events reported more
recently by LIGO.
