At 6'3", I'm one of the tallest members of my family (my younger brother beats me by roughly an inch). Despite the stereotype that just because I'm tall I can tear it up on the basketball court, my hoops skills are average at best. My vertical jump tops out around three to four inches. I can't touch the rim of a basketball goal even if I get a running start at it. However, I'd like to think that if I were 7'8" like Harlem Globetrotters player, Paul Sturgess I could certainly do better than this (or at least put some more showmanship into it).
Nicknamed "Tiny" by the team (because it's original and wacky!), Sturgess is officially listed as the World's Tallest Professional Basketball Player by Guinness World Records. After watching this video from a game a few days ago, my guess is that if they had a "World's Worst Slam Dunk by a Professional Basketball Player", he'd win that too.

While it is impressive that he can effortlessly put the ball through the hoop without leaving the ground, he's a Globetrotter. Their entire routine revolves around putting on a show the crowd won't see at a regular basketball game. At the very least, he could have jumped, or maybe leapt from free throw line, or tucked the ball under his chin and dunked it with his jaw...something!

[Source: Yahoo! Sports]