Vin Diesel On Stilts Isn't Even The Weirdest Thing About This Video

Diesel says he's practicing for 'Guardians of the Galaxy,' but MTV News has a few questions.

Vin Diesel is a special kind of star — the kind of guy who would post a video on Facebook of himself walking around on stilts. We say that because it's exactly what he did Wednesday morning (October 16), and honestly, we're still trying to figure out what's going on.

On the surface, Diesel is just stomping around the set of "Fast and Furious 7" on stilts. But he's actually preparing to do motion capture for Groot, a sentient tree and one of the members of the "Guardians of the Galaxy," Marvel's sci-fi superhero epic planned for next year. He even meets up with Djimon Hounsou (in "Fast and Furious 7" and "Guardians of the Galaxy" too) to briefly discuss his one-line role. (Groot only ever says "I am Groot.")

The actor's name became attached to the role this summer after he spoke publicly about meeting with Marvel and then posted a picture of the character to his Facebook without comment. The studio never acknowledged his involvement in any capacity. Recently, Marvel has made a habit of announcing official casting news on their site. This was the case with James Spader getting the role of Ultron in the "Avengers" sequel, as well as Bradley Cooper voicing Rocket Raccoon in "Guardians of the Galaxy."

So what's the hold-up on an official confirmation that Diesel is Groot? The most likely explanation is that Diesel's reps might be having a hard time nailing down a contract for a one-line character.

But that's not the only thing that's suspicious about this casting.

Why is Diesel practicing walking on stilts? It may all be a joke on his part because with "Guardians of the Galaxy" wrapping up production in London last week, it's unlikely that Diesel would ever perform motion capture for Groot after the fact. That's not how the process usually works.

In the video, Deisel says that he's going to take "Andy Serkis to a whole other level," but the "Hobbit" and "Rise of the Planet of the Apes" actor always performs his motion capture on set. Director James Gunn's brother Sean has been the stand-in for Rocket Raccoon in London, so there was likely a Groot stand-in as well. Adding in Diesel's performance in post-production wouldn't be groundbreaking, but it is another suspicious element in an already strange scenario.

And then there's the Thanos question. The death-obsessed, purple elephant in the room. There hasn't been a word on who will play the villain teased at the end of "The Avengers," despite Gunn and Marvel Studios co-president Kevin Feige confirming that he'll be present in "Guardians of the Galaxy." Thanos could in theory be a CGI character, but Gunn's usage of practical makeup effects and his cameo in "The Avengers" has us thinking otherwise. Before he posted the image of Groot, Diesel hinted that he could play Vision. So if this all turns out to be a ruse and he is actually playing Thanos, it wouldn't be the first trick he's played on Marvel fans.

It's an admittedly crazy bit of speculation on our part, but there's certainly something strange going on with the cast of "Guardians of the Galaxy." But hey, if it gets Vin Diesel on stilts, who are we to complain?

"Guardians of the Galaxy" opens in theaters on August 1, 2014.