#1 Goldberg
A case could be made that Goldberg was possibly the biggest star created on WCW's turf. Goldberg decided to pursue a career in pro-wrestling after a short-lived football career. He was brought in as a silent behemoth, and defeated Hugh Morrus in his debut in 1997.
Thus, one of the greatest streaks in WCW history kicked off, with Goldberg going on to win 173 straight bouts. Goldberg also won the WCW World title on one occassion.
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He debuted in WWE around two years after WCW was bought off. Goldberg enjoyed a dominant run, which kicked off with a victory over The Rock and ended with him putting down Brock Lesnar. He came back to WWE again at Survivor Series 2016, where he squashed Brock Lesnar in a matter of seconds. Goldberg took his rightful spot in the WWE Hall of Fame in 2018.