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 teammate 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.
"He would pour it on them," Payton said.
GP didn't identify which rookies were on the receiving end of the disgusting "prank" -- but he said he at least made an effort to get Shaq back for it all.
Payton explained he'd take the former NBA superstar's underwear from time to time, forcing him to "be free-ballin' all the time."
Not quite eye-for-eye in our book ... but we're sure the effort to return the favor to Shaq was at least somewhat appreciated.