  We report the results of monitoring of the radio galaxy 3C 120 with the Neil
Gehrels Swift Observatory, Very Long Baseline Array, and Mets\"ahovi Radio
Observatory. The UV-optical continuum spectrum and R-band polarization can be
explained by a superposition of an inverted-spectrum source with a synchrotron
component containing a disordered magnetic field. The UV-optical and X-ray
light curves include dips and flares, while several superluminal knots appear
in the parsec-scale jet. The recovery time of the second dip was longer at
UV-optical wavelengths, in conflict with a model in which the inner accretion
disk (AD) is disrupted during a dip and then refilled from outer to inner
radii. We favor an alternative scenario in which occasional polar alignments of
the magnetic field in the disk and corona cause the flux dips and formation of
shocks in the jet. Similar to observations of Seyfert galaxies, intra-band time
lags of flux variations are longer than predicted by the standard AD model.
This suggests that scattering or some other reprocessing occurs. The 37 GHz
light curve is well correlated with the optical-UV variations, with a ~20-day
delay. A radio flare in the jet occurred in a superluminal knot 0.14
milliarcseconds downstream of the 43 GHz "core," which places the site of the
preceding X-ray/UV/optical flare within the core 0.5-1.3 pc from the black
hole. The inverted UV-optical flare spectrum can be explained by a nearly
mono-energetic electron distribution with energy similar to the minimum energy
inferred in the TeV gamma-ray emitting regions of some BL Lacertae objects.
