It seems as though the WWE took the themes for their entrances at WrestleMania 31 from the realm of fantasy. Triple H's entrance was a mix of Terminator and Mortal Kombat (which you can see here), while Stardust decided to dress up as a villain from the Marvel Universe.
As soon as Stardust emerged at WrestleMania, I was wondering why Mister Sinister decided to take up wrestling. The inspiration was obvious and if he had used blue/orange instead of black/orange for his costume, the WWE might have had to answer to Marvel about why they stole their character.
For those who are unaware of who Mister Sinister is, he's mainly a villain from the X-Men comic books. We'd go into his back story and powers, but this is a sports website and his story deserves more justice than a quick blurb. If you'd like the skinny on him, you can find that here.