  We investigate the source eruption, propagation and expansion
characteristics, and heliospheric impacts of the 2020 November 29 coronal mass
ejection (CME) and associated shock, using remote sensing and in situ
observations from multiple spacecraft. A potential--field source--surface model
is employed to examine the coronal magnetic fields surrounding the source
region. The CME and associated shock are tracked from the early stage to the
outer corona using extreme ultraviolet and white light observations. Forward
models are applied to determine the structures and kinematics of the CME and
the shock near the Sun. The shock shows an ellipsoidal structure, expands in
all directions, and encloses the whole Sun as viewed from both SOHO and STEREO
A, which results from the large expansion of the CME flux rope and its fast
acceleration. The structure and potential impacts of the shock are mainly
determined by its radial and lateral expansions. The CME and shock arrive at
Parker Solar Probe and STEREO A. Only based on the remote sensing observations,
it is difficult to predict whether and when the CME/shock would arrive at the
Earth. Combining Wind in situ measurements and WSA-ENLIL simulation results, we
confirm that the far flank of the CME (or the CME leg) arrives at the Earth
with no shock signature. These results highlight the importance of multipoint
remote sensing and in situ observations for determining the heliospheric
impacts of CMEs.
