TV mashups aren’t as popular as they were back in the days of sweeps months, when viewers were treated to such series collisions as “McHale’s Navy” meets “Gilligan’s Island.” Too old? How about “Homicide: Life on the Streets” and “Law & Order”?

Long Beach almost played host to a bit of latter-day TV cross-pollination on Thursday afternoon. Crews from Fox-TV’s “Lucifer,” based on Neil Gaiman’s DC Comics character Lucifer Morningstar, the Devil, who abandons Hell for Los Angeles (six of one…), were filming an episode on Broadway and The Promenade in Downtown Long Beach. At the same time, crews from Fox’s “Lethal Weapon,” based on the movie franchise of the same name, were wrapping up their now-infamous zip-line shoot a few yards to the east on Broadway.

The “Lucifer” crew decided it would be nice to shoot a quick walk-and-talk scene in front of the Pacific Towers, where “Lethal Weapon” filmed on Wednesday. The “Lucifer” crew asked the “Lethal Weapon” crew if they would move a truck so they could film.

Perhaps still shaken from the mess that “Lethal Weapon” was involved with on Tuesday and Wednesday (to recap: A sagging zip-line snagged a Honda CR-V, crushing the front of the car; at least one, and possibly two, fake police cars from the shoot were stolen; and in a staged brawl inside DoLy’s Delectables on the ground floor of the building, stunt fighters accidentally knocked a hole in a wall), the “Lethal” crew, still in the process of striking the set, refused to move.

And there died our hopes for a “Lucifer vs. Lethal Weapon” episode in next November’s sweeps.