Mercury Morris, a running back and kick returner on the Miami Dolphins’ undefeated 1972 Super Bowl team, has died, a family member said. He was 77.

The Miami Herald has confirmed Morris’ death through the Dolphins.

“It is with deep sadness that we announce the passing of Eugene ‘Mercury’ Morris, legendary Miami Dolphins running back and beloved member of the NFL family, at the age of 77,” his son GhostWridah, a Miami-based musician born Troy-Jeffery Morris, wrote on X. “Known for his electrifying speed and dynamic play, Mercury was a cornerstone of the Dolphins’ historic undefeated season in 1972 and a two-time Super Bowl champion. His talent and passion left an indelible mark on the sport, and his three Pro Bowl selections only cemented his place among the football greats.

“Off the field, Mercury was a devoted father, loving brother, loyal friend and pillar in the community. His presence extended far beyond football as he touched the lives of many during his time in Miami.”

Morris was a third-round pick by West Texas A&M and played for the Dolphins from 1969 to 1975. Along with Larry Csonka and Jim Kiick, he helped form what would later become known as the “perfect backfield.”

Morris was a three-time Pro Bowler and two-time Super Bowl champion with the Dolphins, winning the championship again in 1973.

Morris rushed for exactly 1,000 yards and scored a league-leading 12 rushing touchdowns during the 1972 regular season. The Dolphins finished 14-0, then won three more postseason games for the only undefeated season in NFL history.

Csonka also ran for 1,117 yards that year, making Miami the first team ever to have two 1,000-yard rushers in the same season.

“It’s a very sad day for me and our Dolphin family. #NeverForget #22 #72Dolphins #Perfectville,” Csonka wrote on X.

Morris was traded to the Chargers in 1976 and played one season in San Diego before retiring.

In 1982, the Pittsburgh native was convicted of drug trafficking, which was later overturned, but he spent more than three years in prison on a plea deal. He later appeared as a motivational speaker discussing his time in prison.

According to the family statement, Morris is survived by five children: Geno, Maceo, Tiffany, Troy and Elliott, and three siblings.