She has only been seen once, but is occasionally mentioned.

The family also has a pet cat, which is only mentioned occasionally.

Although occasionally mentioned, Alf was not seen again until 1971.

Some other planets are also occasionally mentioned in the series, and their inhabitants sometimes seen.

It is occasionally mentioned on the show by the presenter.

These were generally outside the scope of Marx's own analysis, even if he occasionally mentioned them.

Zilnonpa is occasionally mentioned in the sources up to 1538.

The crime for which the protagonist faces hanging is occasionally mentioned.

She occasionally mentions Lily's strange behavior and methods of raising her children.

Known and addressed simply as "Robot", his full designation was only occasionally mentioned on the show.