Yes, you are seeing that video correctly. Tony Mitchell actually dunked off an alley-oop from teammate Ron Howard who was deep in the stands with the crowd. D-League represent.
Here are more dunk highlights which Tony had while winning his second straight D-League dunk contest.

About Chris Partlow
Recent Posts
UCLA quarterfinals win proves costly
"My concern is for him and his career."
Mike Tomlin makes first public comments since stepping down
“It's been an honor.'
Caitlin Clark shines in return to the court
“I was really just excited."
Cal Raleigh responds to Randy Arozarena: ‘no beef’
"I love Randy, I do."
Miami University aims to be ‘best Group of Six program in the country’
"Our goal is to be the best Group of Six program in the country."
LeBron James passes Kareem Abdul-Jabbar
"Obviously, it's a pretty cool feat."