The Star Trek film universe is in a strange place right now. Star Trek 4 has run into some problems, as Chris Pine and Chris Hemsworth have both dropped out due to salary disagreements. And then there’s Quentin Tarantino‘s puzzling R-rated Star Trek film that Paramount seems very interested in making at some point.

Karl Urban, who is expected to appear in both Star Trek 4 and Tarantino’s Star Trek, offered up some info on the later project, going so far as to call Tarantino’s idea “bananas.” Strong words!

Quentin Tarantino is currently shooting Once Upon a Time in Hollywood, but once he wraps that, the filmmaker is expected to climb aboard the starship Enterprise to bring his wild R-rated Star Trek idea to life. As previously reported, Tarantino pitched an idea for an R-rated Trek to J.J. Abrams, who liked the concept so much he set Tarantino up with a meeting at Paramount. Paramount, in turn, was also impressed with Tarantino’s idea, and assembled a writers room to help hash it out.

Beyond the alleged R-rating, we don’t know a whole lot about Tarantino’s Trek, other than the fact that the filmmaker wants to use the current Star Trek franchise movie cast to star. One of those cast members is Karl Urban, who plays miserable space doctor Leonard “Bones” McCoy. Urban recently appeared at the Trekonderoga convention, where he offered up some insight into Tarantino’s Star Trek (via Trek Movie). The actor didn’t give any plot specifics, but he did confirm that Tarantino’s idea is a bit out-there:

“Quentin Tarantino went in to [producer] J.J. [Abrams]’s offices and pitched him an idea for a Star Trek movie. I know a little bit about what that is, and it’s bananas. So, they are writing that as well. He is currently making a film with Brad Pitt and and [Leonardo] DiCaprio [Once Upon a Time in Hollywood]. So, it is going to be a year away from finishing that.”

Just what, specifically, is “bananas” about Tarantino’s Trek idea remains to be seen, but the potential craziness could have something to do with the proposed R-rating. As Urban tells it, though, the film isn’t going to be rated R because of non-stop vulgarity, but rather to better portray the horrors and dangers of space:

“You shouldn’t worry that it is going to be full of obscenity and stuff. He wants an R-rating to really make those beats of consequence land. If it’s not PG, if someone gets sucked out into space, which we have all seen before, we might see them get disemboweled first…It allows some some breadth…gives him some leeway to do that. To me, that was always one of the things I loved about what DeForest Kelley did. He would actually capture the horror of space. That look in his eyes of sheer terror always struck me when I was a kid.”

And what of Star Trek 4? The film, which is set to be helmed by S.J. Clarkson, ran into trouble recently when Chris Pine and Chris Hemsworth both walked away due to salary issues. Their departure is a fairly big deal, because Pine, as Captain Kirk, is the lead of the film, and Hemsworth, playing Kirk’s father, factors heavily into the story – which involves Kirk reunited with his dead dad via some sort of time travel trickery. There’s always a chance Paramount could re-cast these parts, but Urban thinks everything will work out in the end.

“Hopefully, we get back for another movie, or two of them,” the actor said. “We are just sort of waiting on negotiations. I’m confident we will… I believe the status of the project is really hinging on the availability and the contract negotiations of the two Chrises.”

But what happens if negotiations don’t work out? Urban thinks that would be the perfect opportunity to make the Tarantino Star Trek movie first:

“It is in the hands of Paramount..if we don’t get to make [Star Trek 4] next year with Chris Hemsworth, then that’s okay, let’s make a really good Quentin Tarantino Star Trek movie. You will have to wait longer, but it will be well worth it.”

Of course, Tarantino would want Chris Pine to come back for his Trek as well, which also might complicate matters. For now, we’ll just have to wait and see how this all plays out. Sooner or later, one or both of these films will be made. Hopefully.