Darryl Dawkins, who arrived in professional basketball as a gigantic teenager and became one of the game's fiercest dunkers and most notoriously lovable characters — a backboard-smashing, fun-loving man-child known to fans as Chocolate Thunder from Planet Lovetron — died Thursday in Allentown, Pa. He was 58.Tracey Sechler, a spokeswoman for Lehigh Valley Hospital, confirmed the death. The cause was apparently heart failure, said Robert Tyler, a family friend."Darryl touched the hearts and spirits of so many with his big smile and personality, ferocious dunks, but more than anything, his huge, loving heart," his family said in a statement. "His family — wife Janice; children Dara, Tabitha, Nicholas and Alexis; along with countless family, friends, and fans — all mourn his loss. More than anything Darryl accomplished in his basketball career as the inimitable 'Chocolate Thunder,' he was most proud of his role and responsibility as a husband and father."A larger-than-life figure — at 6 feet 11 and more than 250 pounds, he was pretty large to begin with — Mr. Dawkins made his mark on the sport in a number of ways.Selected as an 18-year-old from Orlando by the 76ers as the fifth overall choice in the 1975 draft, he became the first player to make the leap directly from high school, Orlando Evans, to the NBA. (A year earlier, Moses Malone had jumped from high school in Virginia to the American Basketball Association.)With a sculpted physique, inordinate strength and an unusually accurate jump shot for a man his size, Mr. Dawkins was also mischievous and flamboyant — he was known to wear an electric lime-green suit — and fond of rhyming and hyperbolic fantasy musings.His "Chocolate Thunder" nickname, he often said, was given to him by legendary singer Stevie Wonder, who is blind. "People don't want to believe it. … A guy who never saw me gave me the name Chocolate Thunder," Mr. Dawkins said in 2012.His coaches loved him despite sometimes immature behavior."It was hard to be mad at Darryl Dawkins," his former coach Billy Cunningham said in 2010. "I mean, he would drive you crazy, but then he was a little boy inside. A little boy."Mr. Dawkins had many connections to the Tampa Bay area. As a 6-foot-10 sensation at Orlando Evans High, he led his team in the Roy King Invitational in 1974 in St. Petersburg.In 2000 he was named coach of the upstart Tampa Bay Thunderdawgs of the American Basketball Association 2000. The team went 3-8 before Mr. Dawkins was replaced by Gordon Gibbons.In 1979, with the Sixers playing in Kansas City against the Kings, Mr. Dawkins rose over Bill Robinzine and his powerful dunk literally brought down the basket, shattering the Plexiglas backboard and raining clear pellets onto the floor, and delaying the game by 90 minutes. Mr. Dawkins repeated the feat a few games later.He played 15 years in the NBA. The first seven were with the Sixers, with whom he went to the league final three times and lost each time. For his career, he averaged 12 points and 6.1 rebounds.After Mr. Dawkins' backboard-shattering spree, the league introduced breakaway rim."The first one was an accident, but I wanted to see if I could do it again when I got back to Philadelphia," Mr. Dawkins said in 2004, referring to his most smashingly spectacular dunks. "All the fans were hollering, 'You've got to do one for the home crowd,' so I went ahead and brought it down."Everybody was in awe. Fans were running out grabbing the glass. I felt like I was doing something no other human could do."