Though Jeffrey Dean Morgan has played a lot of heroes in his time, he also has an affinity for portraying complex villains. Viewers have seen him as the conflicted ex-superhero The Comedian in "Watchmen," and in a few short minutes, he stole the show with his debut as Negan on AMC's "The Walking Dead."

But while Negan may be the most infamous and perhaps complicated antagonist in "Walking Dead" history, he may have nothing on Sam, Morgan's character in the new Mexican thriller "Desierto." Co-written and directed by Jonás Cuarón ("The Year of the Nail") and produced by his brother, Alfronso (whom he co-wrote "Gravity" with), "Desierto" centers on a group of undocumented Mexican immigrants being hunted down by Sam. As he picks them off one by one, the film eventually becomes a cat-and-mouse game between him and Moises (Gael Garcia Bernal). Without spoiling too much, there's a ton of gut-wrenching violence that involves gunplay, cacti, and Sam's equally terrifying dog, Tracker.

Is it subtle? No -- but that's not the point. Instead, the film combines the thrills of a blood-soaked, tightly ratcheted B-movie with a message that's undeniably political, especially when considering all the bile that's been spat about the supposed dangers of Mexican immigration during the current election cycle. The result is a movie unlike anything else that's come out this year -- as thought-provoking as it is viscerally entertaining. We checked in with Morgan about the political implications of "Desierto," the psychology behind Sam, and what it was like working with a vicious dog as an acting partner.

CBR: I just watched "Desierto" this morning

Jeffrey Dean Morgan: Well, that's a hell of a way to wake up.

I knew the general plot, but I didn't know how intense it was going to be. It was an interesting way to start my day.

[Laughs] It's like a good cup of coffee.

The guy you play, Sam, is obviously not a good person. However, after he makes his first kill, there's a moment where he gets back in his truck and is so excited and revved up. But then he just kind of deflates. It's a very human moment. Do you have any kind of sympathy for him, or did you at least try and build a backstory with him that psychologically made sense?

That was a full-on improv moment. I wasn't sure how I was going to play it. Jonás and I went back and forth 100 times on it: "Is this something Sam does all the time, or is this his first time?" I decided at that moment that this was probably the first time he'd shot someone and killed them. He just snapped. It was just one of those things where the cameras were rolling and Sam had this moment of euphoria that then goes into "What the fuck have I just done?" And now he's in. Now he's got to finish this job.

But we had a lot of talks about who this character was and what his motivation was. We actually wrote scenes together that explained or justified, at least in Sam's mind, why he would do these things. I remember we did an additional day of shooting three months later, and we met in La Paz. Jonas showed me a rough cut of the film that had these scenes we'd written. There was a phone call to [Sam's] wife, and he had a scene right before he kills somebody where he explains his reasoning for being this douchebag.

But it was too much. I don't think there's any way someone like that can justify their actions, and I don't think the audience cares to see it or needs to see it either. So we both looked at each other and [said] "Let's get rid of it." Frankly, the less you know about his motivation, the [more] you get into the story. I think sometimes the problem with film and TV is that we over-explain. We try to explain every moment and every thought. I liked that, in this movie, we don't really explain anything. People can say he's one-dimensional, but I like to think that he's not. There's this moment where he's looking for Gael's character...

It's almost like he's going to commit suicide.

That's interesting. I think that probably was a thought. But I think more important is that it's over for him. When he's sitting at that campfire, he's done. He's done chasing them. He's ready to go home. He's realized what he's done, and maybe he's gone too far. He thinks it's maybe time to call it a day for old Sam. And he probably is going to off himself. But then the dog catches scent of them and it turns into a whole new third act of the film. But at that point, I think it was done for him. Again though, there's no justification for any of his actions.

He does have this nice relationship with his dog, Tracker, even though the dog is also murderous and horrible. Did you get close to the dog who played Tracker on set?

Well, there were three dogs, and they were all a different level of viciousness. [Laughs] There was one dog that you could kind of interact with. He was okay. But the other two, the trainers just kept you away from. They weren't real good around people. I remember once, they put me in the truck with the wrong dog. Sam's swigging a thing of whiskey, and I reach over to say "Good boy, Tracker," or whatever it is, and this boy turned on me, and I felt the teeth brush the side of my face in a full snap with this horrendous sound. I didn't move. I just looked forward. I knew Jonás was right there and our DP was right there, so I just slowly opened the car door and fell to the ground. It was maybe the closest I've been to at least serious maiming in quite some time.

But the dogs, as you know, having seen the movie, are just terrifying. This dog is the new Jaws. I've never seen anything like it. He made Cujo look sweet. Great to work with, though. When climbing those cliffs, the dog was incredible to work with. That dog may have stolen the show.

When Jonás wrote the script with Mateo Garcia, do you know if they had any discussions about the current political climate, and the film's relation to that? Or did the script get written after Donald Trump had already made his remarks about Mexican immigrants?

That all came later. Jonás really began writing this script about 8 or 10 years ago. I mean, we shot this movie well before any of this shit. We premiered two years ago at Toronto, for God's sake. And STX held on to it because Trump was in the running, and made his fucking speech about Mexican immigrants being murderers and rapists and all that. So, very smartly, they held on to it. I don't think that anyone could have anticipated that he would get the Republican nomination.

But they held on to it, and now here we are. There's a very specific reason it's being released right now, because it has become this hot-button issue.

"Desierto" is in theaters now.