  We study the holographic interpretation of the bulk instability, i.e. the
bulk Lyapunov exponent in the motion of open classical bosonic strings in AdS
black hole/brane/string backgrounds. In the vicinity of homogeneous and
isotropic horizons the bulk Lyapunov exponent saturates the MSS chaos bound but
in fact has nothing to do with chaos as our string configurations live in an
integrable sector. In the D1-D5-p black string background, the bulk Lyapunov
exponent is deformed away from the MSS value both by the rotation (the infrared
deformation) and the existence of an asymptotically flat region (the
ultraviolet deformation). The dynamics is still integrable and has nothing to
do with chaos (either in gravity or in field theory). Instead, the bulk
Lyapunov scale captures the imaginary part of quasinormal mode frequencies.
Therefore, the meaning of the bulk chaos is that it determines the thermal
decay rate due to the coupling to the heat bath, i.e. the horizon.
