What's that line about the oldest ride in the park having the longest line? It's been more than 20 years since luchador Rey Mysterio Jr. reinvented cruiserweight wrestling, but after a run in ECW, a breakout turn in WCW, and a decade-plus WWE tenure that saw him become a three-time world champion, Mysterio is still proving himself to be one of the best workers of all-time. Mysterio left WWE in 2015 to rejoin the lucha libre organization where he first became a star, AAA. After big matches with - and against - fellow stars Alberto El Patron and Myzteziz, Mysterio joined the company's sister organization, Lucha Underground. His tenure is expected to be short-lived, though and many feel Mysterio will be back in WWE before the year is through. Years of injuries and general wear and tear have slowed Mysterio down; he's no longer performing dragonranas or quebrada DDTs like it's the '90s. That stuff's just the frosting on the cake, though - Mysterio is a veteran who knows what it takes to make a classic match, moreso than just about anyone else in the business. He's invaluable to any promotion.