  During a systematic search for supermassive black holes (SMBHs) not in
galactic nuclei, we identified the compact symmetric radio source B3 1715+425
with an emission-line galaxy offset ~ 8.5 kpc from the nucleus of the brightest
cluster galaxy (BCG) in the redshift $z = 0.1754$ cluster ZwCl 8193. B3
1715+425 is too bright (brightness temperature $\sim 3 \times 10^{10}$ K at
observing frequency 7.6 GHz) and too luminous (1.4 GHz luminosity $\sim
10^{25}$ W/Hz) to be powered by anything but a SMBH, but its host galaxy is
much smaller ($\sim 0.9$ kpc $\times$ 0.6 kpc full width between half-maximum
points) and optically fainter (R-band absolute magnitude $\sim -18.2$) than any
other radio galaxy. Its high radial velocity $\sim 1860$ km/s relative to the
BCG, continuous ionized wake extending back to the BCG nucleus, and surrounding
debris indicate that the radio galaxy was tidally shredded passing through the
BCG core, leaving a nearly naked supermassive black hole fleeing from the BCG
with space velocity $> 2000$ km/s. The radio galaxy has mass $< 6 \times 10^9$
solar masses and infrared luminosity $\sim 3 \times 10^{11}$ solar luminosities
close to its dust Eddington limit, so it is vulnerable to further mass loss
from radiative feedback.
