Kurt Feltenberger wrote:
> ...when a massive CME hit a planet, that it had the potential
> to "stretch" or "pull" the magnetic fields out of shape and
> elongate them in a direction away from the sun and went on to
> suggest that there could be some unexpected "side effects" of
> such an event happening.
> ... 1.  Would/could this happen?

The distortion would be small even from a large coronal mass ejection,
but there would be effects.

Planetary magnetic fields are either predominantly intrinsic or induced.
In our solar system, Mercury, Earth and the gas giants have intrinsic
magnetic fields due to activity in their cores - the 'dynamo' concept.

The normal interaction with the solar wind produces the characteristic
shape of a leading bow shock with a trailing tail. The magnetic field
forces the bow shock to be several planetary diameters away from the
upper atmosphere.

e.g.
https://en.wikipedia.org/wiki/File:Structure_of_the_magnetosphere-en.svg

or second figure here:
https://genesismission.jpl.nasa.gov/science/module4_solarmax/Magnetosphere.html

Note that an intrinsic field allows the trapping of charged particles
within it, giving rise to radiation belts.

The other planets and moons in the solar system have induced magnetic
activity from the interaction with the solar wind (and the gas giant
they orbit for some of the moons).

Earth's moon also has some remnant magnetism from the rocks in the crust
and mantle.

The bow shock can interact with the upper atmosphere or planetary surface.

e.g. figure 4.3 here:
https://www.nap.edu/read/10993/chapter/6

So a given coronal mass ejection or superflare would distort the shape
of the magnetic field to some small degree, but you would need very big
events to experience effects near or on the surface of an Earth-like planet.

> 2.  What might be the "side effects" if it did?

The Carrington event is a good example, as Richard Honeycutt and Bruce
Johnson pointed out:
- Aurorae visible at very low latitudes
- Induction of currents in long conductors (telegraph wires heating,
causing fires) - extrapolate to modern power and telecommunication grids...

A lesser version happened in 1989 in Quebec:
https://en.wikipedia.org/wiki/March_1989_geomagnetic_storm

As previously noted by Richard Aiken, satellites would be vulnerable to
changes in their radiation environment if the radiation belts were
distorted. This may lead to disturbed communications, control loss or
total systems failure depending on satellite altitude, age and radiation
hardening.

Long-distance radio communications would be affected via disturbing the
ionosphere.

The effects on planets or moons with induced magnetic fields would be
more intense.

Certain types of stars will have more frequent storm and flare activity
(e.g. M-type main sequence) - the habitable zone is closer in so the
effect intensity will be proportionately bigger for Earth-like worlds.

For a detailed high-level treatment I would recommend these reports from
the U.S. National Research Council:
- Severe Space Weather Events: Understanding Societal and Economic
Impacts (2009)
- Solar and Space Physics: A Science for a Technological Society (2013)

Rob O'Connor