The 'Avengers: Age Of Ultron' will be a gateway to Phase 3. The worst kept secret is that Thanos will be waiting at the end as the main villain. The casting may have a shocker: Mel Gibson?

It was previously reported that Robert Downey Jr. has been requested, or even demanded that Marvel award a peripheral role for Mel Gibson and/or Jodie Foster.

Radar Online reported the Downey demand. Citing an unnamed source:  

"He wants to bring Mel and Jodie into the Marvel universe. It's been a longtime dream of Robert's to help Mel and Jodie reach similar big box office heights like the ones he's achieved in recent years."

"Robert is very big into working with his friends. Ashley Hamilton and Iron Man 3 director Shane Black both credit him with making the final push to get them hired."

The chances are slim, but Marvel has yet to cast Thanos, and, as MTV suggests, Mel Gibson would look the part, at least:

"Let's say Downey really does want Gibson (and Foster) in a Marvel movie. And let's say Marvel is intrigued by the idea. Who is Gibson best-suited for? The answer should be clear, for anyone who takes even a quick look at the actor's snarling stare, his prominent chin, his toothy smile, and his blue face-paint circa "Braveheart."

The answer, if you didn't get it, is Thanos."

It is MTV and their rationale borders on superficial, but come to think of it, Mel Gibson was a good actor, and even senior A-listers are starting to make a superhero appearance. Robert Redford did it in "Captain America: The Winter Soldier" and Michael Douglas was recently cast as Henry Pym in "Ant-Man."

DC is mounting a casting war with Dwayne Johnson, Bryan Cranston and Denzel Washington being connected with "Batman Vs Superman." If they can get one of those big names, who will Marvel match? James Spader is good, but they need to take it up a notch for Thanos.

The rumor is unconfirmed, and Thanos was just a suggestion by MTV. It's not a fact, but even the most far-fetched rumor can turn to reality in Hollywood.