Wrestling legend Kevin Sullivan -- who was famously one of Hulk Hogan's biggest rivals in the 1990s -- has sadly passed away.
The WWE confirmed his death on Friday morning ... writing in a statement that Sullivan was "a unique and influential figure in sports-entertainment history."
"Sullivan found success both in the ring and behind the scenes with his penchant for far out ideas that pushed creative boundaries," the org. added.
Sullivan was 74 years old.