For a few intense years in the late 1990s, WWE was in serious danger of going out of business due to the rise of WCW. World Championship Wrestling became the company's direct competition, and thus, the 'Monday Night Wars' became a thing. A very popular thing.The two companies went head-to-head on primetime every Monday night, with RAW and Nitro airing simultaneously. While WCW's flagship show took an 83-week lead over its WWE (then WWF) equivalent, it was Monday Night RAW that won out in the end.This was thanks to a creatively fulfilling period, which saw WWE create a barrage of new stars. WCW, on the other hand, focused on veteran names. WWE bought out its competition in 2001, emerging from the battle as the confirmed victor.However, despite that being said, WCW did have a lot of young talents. Some of them were so young that they are still a part of regular WWE programming today - be it RAW, SmackDown, or elsewhere.Here are seven current and (semi) active WWE stars who have appeared in WCW.#7 Rey Mysterio of WWE SmackDownThe match that put me on the map!Definitely my favorite & #1 match of all time! 🙏🏼Eddie 🇲🇽🖤🇺🇸 #Love&MissU https://t.co/iKktl5jHiG— ♛Rey Mysterio❔ (@reymysterio) October 26, 2020Out of all the WWE Superstars on WWE's current main roster, Rey Mysterio is the most obvious name on this list. He was in WCW for five years, following a short but successful stint in ECW under Paul Heyman. Mysterio made a name for himself in WCW's cruiserweight division.In fact, his very first match over there was for the WCW Cruiserweight Championship. Mysterio's most notable outing in the company came at Halloween Havoc 1997. He defeated Eddie Guerrero in a Title vs. Mask match to win the Cruiserweight title, having a star-making performance in the process.While he had the reputation of being a 'giant killer' - defeating Kevin Nash and Bam Bam Bigelow's likes - WCW booked Mysterio to unmask himself. As a result, The Master of the 619 lost a lot of what made him special. This was a mistake WWE never made, following his signing in 2002.With one hand... "There goes @reymysterio." 👀 @WWETheBigShow WCW World War 3, 11/24/96 ▶️ https://t.co/8zfWtTXf2u pic.twitter.com/KrYpHQOiFN— WWE Network (@WWENetwork) November 24, 2020Rey Mysterio has gone on to legendary heights under Vince McMahon, winning multiple Championships and becoming a major star. He is a guaranteed WWE Hall of Famer, thanks to the impact he has had on today's generation of stars. Mysterio is also now grooming his son, Dominik Mysterio, who is at the start of his WWE career.