Quick: What’s the most influential thing about Breaking Bad, the hugely acclaimed AMC drama about a high school chemistry teacher who starts cooking meth to build up a nest egg for his family, in the wake of his cancer diagnosis?

You could make an argument for how the show heightened the antihero drama, or for how it was one of the most smoothly executed serialized dramas in history. But it was more of an evolutionary step than a revolutionary one in terms of both of those categories.

It wasn’t as big of a break from previous TV tradition as, say, The Sopranos was. That show was the first major hit drama to center on an unrepentant bad guy who did terrible things. And when it came to serialization, Breaking Bad was building on ground trod by shows like The Wire and even Buffy the Vampire Slayer.

But there’s one element of Breaking Bad that’s everywhere on TV right now. It’s even on an otherwise gentle drama like This Is Us.

Have you thought of it? I’ll give you a bit. Ready?

Breaking Bad did something genuinely new with TV cold opens

It was the show’s cold opens.

In TV terms, the "cold open" is everything that airs before the opening credits. The vast majority of shows that do cold opens do one of two things.

The first, most common type of cold open is one that sets up everything that’s going to happen in the episode. It catches us up on where the characters are, and it sets up the stories for the episode to come. These frequently last lengthy amounts of time — sometimes even 10 minutes or more. (Famously, The Good Wife would sometimes delay its opening credits for 15 minutes or so.)

The other type of cold open is one that introduces the case of the week, usually by seeing it happen. On a cop drama, this might be the discovery of the corpse of the week. On The X-Files, it was always some mysterious weirdness that ensnared some normal small town citizen. And on Six Feet Under, it was the introduction of the person who was going to die and give the Fisher family a cadaver to work with.

Technically speaking, Breaking Bad’s cold opens are a version of the type two cold open. After all, Breaking Bad creator Vince Gilligan got his big break on X-Files. But the Breaking Bad cold opens take things a step further. Rather than consistently introducing one plot element (a corpse, a monster, etc.), they consistently expand the show’s world, by exploring new corners of it.

In essence, they’re disconnected short films that sometimes have nothing at all to do with the episode that follows. They dig into the characters’ backstories. They set up plot points that won’t pay off for several weeks. They establish how the drug trade at the series’ center functions. In at least one case, they were even a music video.

They functioned a little bit similarly to how many comedies use their cold opens for a disconnected comedic sketch featuring the regular characters. But those comedies rarely used their cold opens to expand their worlds, which were intentionally tiny to begin with. Those comedy sketches usually went small; Breaking Bad intentionally went huge.

This is everywhere on TV now

As mentioned, these sorts of cold opens are everywhere on TV right now. It’s easy to see why, too: They allow for world-building in a way that doesn’t necessarily require getting the main characters involved.

For instance, there’s an episode in the first season of the USA alien-invasion drama Colony (which returns for its second season in early 2017) in which the cold open follows a minor character who had been captured by the aliens earlier in the season, catching up with him as he goes about his daily routine in prison.

At the very end, we learn the location of his prison: on the surface of the moon. The rest of the episode has next to nothing to do with this, and the series never wraps back to it, outside of a couple characters spotting an odd facility on the face of the moon through a telescope. But we know now that there’s a moon prison on this show that will factor into the series again at some point.

Needless to say, the Breaking Bad approach is most popular with genre series. Both The Walking Dead and especially its spinoff Fear the Walking Dead have used them, as has AMC’s comic book adaptation Preacher.

But it’s also been interesting to watch this sort of cold open turn up on This Is Us, which uses just such a device in its upcoming third episode (which airs tonight) to delve into one character’s secret history. (A more traditional cold open featuring the regular characters follows that sequence, but the use of such a sequence is notable.)

There are other non-genre shows that use the device as well. Variations on it were used at several times in The People v. O.J. Simpson. And they’re used on Breaking Bad spinoff Better Call Saul, which likely isn’t surprising.

The Breaking Bad cold open doesn’t work for every TV show. It probably wouldn’t work on a more traditional workplace drama or cop show, and it’s hard to see a comedy getting too much use out of it (though You’re the Worst has occasionally flirted with such a device). But it’s been fun to watch it spread throughout TV, giving many different shows a chance to play with new types of storytelling, even if it’s only for a few minutes per week.