  We report on a radiopolarimetric observation of the Saturn-Jupiter Great
Conjunction of 2020 using the MeerKAT L-band system, initially carried out for
science verification purposes, which yielded a serendipitous discovery of a
pulsar. The radiation belts of Jupiter are very bright and time variable:
coupled with the sensitivity of MeerKAT, this necessitated development of
dynamic imaging techniques, reported on in this work. We present a deep radio
"movie" revealing Jupiter's rotating magnetosphere, a radio detection of
Callisto, and numerous background radio galaxies. We also detect a bright radio
transient in close vicinity to Saturn, lasting approximately 45 minutes.
Follow-up deep imaging observations confirmed this as a faint compact variable
radio source, and yielded detections of pulsed emission by the commensal
MeerTRAP search engine, establishing the object's nature as a radio emitting
neutron star, designated PSR J2009-2026. A further observation combining deep
imaging with the PTUSE pulsar backend measured detailed dynamic spectra for the
object. While qualitatively consistent with scintillation, the magnitude of the
magnification events and the characteristic timescales are odd. We are
tentatively designating this object a pulsar with anomalous refraction
recurring on odd timescales (PARROT). As part of this investigation, we present
a pipeline for detection of variable sources in imaging data, with dynamic
spectra and lightcurves as the products, and compare dynamic spectra obtained
from visibility data with those yielded by PTUSE. We discuss MeerKAT's
capabilities and prospects for detecting more of such transients and variables.

Instrumentation and Methods for Astrophysics;Earth and Planetary Astrophysics;High Energy Astrophysical Phenomena