In our compendium of great Duke dunks the other day, we neglected to add Phil Henderson's phenomenal 1989 dunk over Alonzo Mourning. For those who weren't following him in high school or were too young to remember, Mourning came into college with a ferocious reputation as a shotblocker: in one high school game he blocked 27.
He was also to an extent riding Patrick Ewing's Georgetown glory: Ewing was insanely intimidating, particularly as a freshman. In the NCAA Tournament, against (we think) Oregon or Oregon State, he blocked a shot on one end then beat everyone down court to dunk on the other.
The game was effectively over and it was only about three minutes in.
In the context of the Georgetown big men myth - also picked apart by Christian Laettner - Henderson's dunk was astonishing.