20 Things You Didn’t Know About Iron Man 2
13. Whiplash Originally Had A Loki Tattoo On His Neck
As mentioned, Mickey Rourke put a ton of effort into researching and selecting tattoos for Ivan Vanko which would inform his upbringing in a materially accurate way.
Whether it was Rourke's decision or simply that of a makeup artist, though, Rourke actually had a tattoo of the trickster God Loki applied to his neck while shooting his role in the film.
It was only in post-production that producers, who were imminently due to start shooting Thor, realised that it might confuse fans and make them believe that Whiplash was linked to the MCU's own Loki (Tom Hiddleston).
And so, the Loki tattoo was digitally removed during post-production.