Shaquille O'Neal was a horrific teammate to rookies back in the day ... so says Gary Payton, who claims the Big Diesel used to pour his waste on guys who were using the bathroom.
Payton, who was Shaq's teammates for one year with the Lakers and then two years with the Heat in the 2000s, explained how the vile acts would go down during a recent interview with Vlad TV.
The Glove said Shaq would go to the bathroom in a bucket "for about a week" -- and then dump it on unsuspecting rookies who were in stalls.