I have always been a big fan of the Marvel comics series. And Hulk has been my favourite when it comes to sheer muscle.
But this time Thanos completely crushed Hulk. Thanos had big arms that are well developed.
Sheer size, massive Biceps brachii muscle to match with fully developed Brachialis muscle. And a matching Triceps lateral head to give it that 3 dimensional powerful look.
So, here are my top pick for building 3-D arms
Triceps Lateral Head
Narrow Grip Bench Press
https://www.bodybuilding.com/
Brachilias
Preacher Reverse Curl
https://www.bodybuilding.com/
Biceps brachii
Hammer Curls
https://www.bodybuilding.com/
For a complete 6 Weeks Massive Arms program go here
https://anextrarep.com/