Ivan Reitman, the director of the first two “Ghostbusters” films and the producer of the third all-girl version, opened his mind at Comic-Con recently about a possible fourth movie that may be released in 2019. “Ghostbusters 4” will likely not be a sequel to the all-girl film since it tanked at the box office. That leaves a number of intriguing possibilities, some of which made possible by modern CGI technology.

‘Ghostbusters: The Next Generation’

The easier approach would be to have one or more of the originals come back to train a new generation of younger Ghostbusters.

Almost 30 years have passed since “Ghostbusters 2” so one could assume that the original group is long retired. However, a sudden surge in paranormal activity could bring about the necessity of a new group of specialized exterminators.

‘Ghostbusters: The Band Gets Back Together’

In this scenario, the old guys get Back Together for one last adventure. Of course, Bill Murray, Dan Aykroyd, and Ernie Hudson are not as spry as they used to be and Harold Ramis is dead. The last problem could be addressed with the same CGI wizardry that brought back the Grand Moff Tarkin in “Rogue One.” The question arises, would Egon be a living person still or could they make him the first Ghostbuster who is, himself, a ghost?

On the one hand, bringing back Egon could be seen as honoring the character and the actor who played him by giving him one last occasion to strut on the big screen. On the other hand, fans might conclude that using CGI to bring back an old character is such a way is being disrespectful. It could go either way.

‘Ghostbusters: The Lost Adventures’

The same CGI that de-aged Carrie Fisher to make her a younger Prince Leia in “Rouge One” could be used to create younger versions of the Ghostbusters in a “lost adventure” set in the 1990s. The approach could set up the possibilities of sequels to a lot of other long, dormant franchises. The technology would have avoided the problem of some of the later “Star Trek” films or even the later Roger Moore Bond pictures when it was evident to one and all that the principals had become too old for all of that running and jumping.

But who would be the big bad?

The first “Ghostbusters” featured a murderous goddess named Zul as the villain. The second film brought back to existence an ancient tyrant named Vigo. Who could be brought back from another dimension or the afterlife that could top those two? Satan himself, perhaps?