  We investigate (2+1)-dimensional black strings in the Kaluza-Klein spacetime.
The system is classically stable as long as the horizon size is much larger
than the size of the compact space. Semiclassically, however, the horizon size
shrinks gradually due to the energy loss through the Hawking radiation.
Eventually, the system will enter into the regime of the Gregory-Laflamme
instability and get destabilized. Subsequently, the spherically symmetric black
hole is formed and evaporated in the usual manner. This standard picture may be
altered by the dynamics of the internal space which induced by the Hawking
radiation. We argue that the black string is excised from the Kaluza-Klein
spacetime before the onset of the Gregory-Laflamme instability and therefore
before the evaporation.
