Every now and then an actor or actress will appear in a work of fiction as themselves and it sets my entire brain on fire. This is mostly a defect, to be sure, a flaw in the wiring somewhere in my head that evolution or good sense should have chewed up before we got here. But it’s infected me long enough that I’ve come to find enjoyment in it. I’ve even turned it into a game I play when I’m bored or awake or with some other sickos who operate on a similar wavelength. I’m going to go ahead and pass it on to you now. You are welcome and I am sorry.

Here’s how this works, as quickly as possible: If an actor or actress appears in a show or movie as himself or herself, then that, in theory, means everything he or she has starred in also exists in the universe of that fictional show or movie. And so do the casts of those projects. Which, if you follow the trail down the path far enough, and well past the signs telling you the terrain gets dicey ahead, can create some pretty wild little conundrums where a snake swallows its own tail whole.

There are really only four rules to any of this:

• You have to start with an appearance where an actor or actress appears as themselves on a show or in a movie
• You have to try to track everything back to the other actors or actresses in the project until the whole thing folds itself in half
• It’s not so much about how fast you can get there as it is how much fun the journey is
• Try not to use SNL or 30 Rock or any voice work in an animated project because that’s kind of cheating

An example will help. Let’s take the most recent season of Only Murders in the Building, the last show I watched that got these specific juices flowing. Mel Brooks made a brief guest appearance as himself on the show, via FaceTime. Here, look at Mel.

That’s great! I love Mel Brooks! It was cool to see him pop up in a fun show I watch!

But consider this: If Mel Brooks exists as himself in the world of Only Murders in the Building, then that means everything else Mel Brooks has done in his lengthy Hollywood career also exists in the world of the show. Like, say, Spaceballs. Great movie. One of the best. But if Spaceballs exists in the world of Only Murders, then that means its cast does, too. Which means John Candy exists, because John Candy was in Spaceballs as a half-man, half-dog hybrid named Barf. And if John Candy exists, then so does National Lampoon’s Vacation, because he was also in that movie. With me so far? Good. Because this is where things get weird.

Vacation starred Chevy Chase. Who was also in Three Amigos. With…

… Steve Martin and Martin Short… who star in Only Murders as fictional characters named Charles and Oliver. Which means, if we follow this thread, that there’s a marginally famous murder podcast on this show that is hosted by a longtime network television actor and a Broadway director who look and talk exactly like very famous comedians Steve Martin and Martin Short, who also exist in this world, and no one — not even Mel Brooks! — has brought it up in three seasons.

That’s weird, right?

Cool.

We can make it weirder.

Matthew Broderick also appeared as himself in this season of Only Murders. It was loosely fictionalized, sure, but it was very much him, the guy, who was in The Producers and everything else over his long career. Stay with me.

If Matthew Broderick exists, then so, one assumes, does Ferris Bueller’s Day Off. Which means Alan Ruck, who plays Cameron in that movie, also exists. Which means so does Succession, where Ruck played one of the older Roy children and Stephen Root played a political mega-donor named Ron Petkus. And if Stephen Root exists, then so does The West Wing, because Root was on that show, too, in the final few seasons. And Rob Lowe was on The West Wing for a while, many years before he was on Parks and Recreation, a show that also featured a doofus political candidate named Bobby Newport, who was played by… Paul Rudd.

And Paul Rudd guest-starred on this season of Only Murders, too. Not as himself. As a famous movie star who was murdered on the opening night of a play he was starring in. And that means, again, based on logic (or something resembling it), that this entire season of the show was about the investigation of a murder of a famous actor who looks and sounds exactly like Paul Rudd — a real person in this world! — and no one mentions it at all, ever, not even on the podcast about his murder.

Again, it’s weird.

Again, we can make it weirder.

If Paul Rudd exists, then so does Bill Hader, which you can prove a million ways but I will do here using this Conan clip, both because it’s the quickest and because it’s fun to watch.

If Bill Hader exists, then so does the two-part episode of Documentary Now! where he played an even goofier version of Robert Evans. It’s really good. I might watch it again tonight.

Anyway, that episode also featured Anne Hathaway as herself, as a presenter at a fictional Academy Awards ceremony in the mockumentary about the fictional movie studio titan, which is a lot of fun for me to explain. Say hello to the people, Anne.

So, by tracking this all through Rudd and Hader, we now can prove that Anne Hathaway exists in the Only Murders universe.

Well, Anne Hathaway was in The Devil Wears Prada with… Meryl Streep.

Meryl Streep guest-starred on this season of Only Murders as a struggling actress named Loretta who became Oliver’s love interest.

Which means rooms full of people watched a struggling actress who looks exactly like Meryl Streep and a Broadway director who looks like Martin Short make out a little and they said… nothing about it. Think about that for a while this week.

We’re really rolling now. Let’s keep going.

Meryl Streep — the real person, who, as we have shown, basically has to exist in the Only Murders universe — starred in Mamma Mia! with Amanda Seyfried, who starred in Mean Girls with Tina Fey, who also has appeared in multiple seasons of Only Murders as a villainous blonde podcast host named Cinda Canning. And as fun as it was to type the phrase “villainous blonde podcast host” the important thing here is that Tina Fey and her blonde doppelgänger both exist on Only Murders.

And if Tina Fey exists in the world of this show, then so does the movie Date Night starring her and Steve Carell. And that means The 40-Year-Old Virgin exists because Carell is in that movie, as is Paul Rudd — we could have gotten here a few ways — and a young Seth Rogen. Seth Rogen was later in two pretty good Neighbors movies with Zac Efron. Zac Efron was in a few High School Musical movies with Vanessa Hudgens. Vanessa Hudgens was in Spring Breakers with…

Selena Gomez.

Who stars in Only Murders in the Building.

Which means there’s some struggling podcast host bumbling around Manhattan who looks and sounds exactly like international megastar and frequent paparazzi subject Selena Gomez — who, again, exists on the show via connections to Efron and Rogen and Carell and Fey and Seyfried and Streep and Hathaway and Hader and Rudd and Root and Ruck and freaking Matthew Broderick — and not one person in three seasons of the show has been like “YO HOLY CRAP IS THAT WORLD FAMOUS MUSICIAN AND ACTRESS SELENA GOMEZ???” when they see her walking down the street.

The important conclusions here are as follows:

• I’m fine and/or normal
• This game is more fun and chaotic than Six Degrees of Kevin Bacon
• I somehow did this whole thing without using Jon Hamm once, even though Jon Hamm has appeared in enough things — often as himself! — that we should go ahead and name the whole game after him

Again, you are welcome and I am very, very sorry.