I heard about Mercury Morris' death via Joe Posnanski's blog:

At an event the other day, we talked about great nicknames, and I said the greatest football nickname of all time is Night Train Lane. I do still believe that... but Mercury Morris has to be right up there. His full name was Edward Eugene Morris, and he was a running back and kick returner for the Dolphins during their glory years, 1969-75. He's best known for 1972, of course, when he and Larry Csonka provided the lightning and thunder for the undefeated Dolphins. 

The New York Times obit digs deeper (Joe is on a book tour), reminding us that there were three men in that Dolphins backfield: Morris, Csonka, and the wonderfully named (and spelled) Jim Kiick. I tend to associate Csonka and Kiick. They were both white, thick, low to the ground grinders who barrelled through the line. Mercury was opposite in every respect: black, lean, and (in my memory) forever dancing along the edges and down the sidelines. He was beautiful to watch.

He started out mostly as a kick returner but his star began to rise in 1972 when coach Don Shula decided to use him more. And then five games into the season, Bob Griese got injured and was replaced by the ancient Earl Morrall, and, as the Times obit reminds us, the running game became more important than ever. Kiick's attempts actually went down that season, from 162 to 137, while Csonka's rose (195 —> 213), but Morris was the real difference:

Those 12 rushing TDs over 14 games led the league, Morris and Csonka became the first backfield to both gain 1,000 yards, and the Dolphins went undefeated on their way to a Super Bowl VII victory over the overmatched Washington Redskins, 14-7. The next season, Morris led he league in yards-per-attempt (6.4!!) as Miami repeated as Super Bowl champs by dispatching my overmatched Minnesota Vikings 24-7. Yeah, I hated them. The oddity is I that liked a lot of their players, particularly Morris and wide receiver Paul Warfield. I don't know why. They had grace. They were fun to watch.

How many guys from that '72 club are in the Hall of Fame? I read six, not including Shula. In order of induction: Warfield, Csonka, offensive lineman Jim Langer, Griese, guard Larry Little, and linebacker Nick Buoniconti. Not Morris. His career was too short, I guess. Csonka, for example, played from 1968 to 1979 while Morris began a year later and was done by '76. He made the Pro Bowl three times.

The Times obit goes into his post-career drug problems which I vaguely remember. In the '80s he was busted for cocaine trafficking, sentenced to 20 years (!), but evidence had been suppressed at his trial and he was released after three. Did he sue the state? He should have. No reason was given for his death Sunday at age 77.