#1 Turned down WCW: The Undertaker

One of the greatest stars in WWE history, fans have long-pondered what would have happened if The Undertaker had jumped ship to WCW during the Monday Night War.
Though he was just one star, having the Deadman be the latest in a long line of WWF talent could've been the game changer in the war, if he'd followed in the footsteps of stars like Hulk Hogan and Bret Hart.
According to Kevin Nash, the Demon of Death Valley was indeed offered a contract by WCW, and was close to signing. If he had, Undertaker would've joined the company under real name Mark Calaway, as the Biker character.
Instead, the Phenom remained loyal to the WWF, debuting the new character at Judgement Day 2000, and WCW were gone less than a year later.