Robin Lopez of the Chicago Bulls had a fun moment with the Toronto Raptors mascot.

Check out the clip below, posted by the Bulls on Twitter. It seemed like a fun and harmless moment between Lopez and the mascot. But towards the end of the video, something happened that triggered Lopez.

Contrary to popular belief, Robin Lopez is not only known for his angry fits during games. We've seen him getting ejected in several games after violently disagreeing to a call.

But for those following him closely, these antics with NBA mascots are not new. He has built an unusual relationship with these mascots. And below is a clip of his ‘fights' with them:

In an interview with Howard Beck of Bleacher Report in 2015, Robin Lopez revealed why he hates mascots and even singled-out a specific one which he had a bad past with.

“I feel like my earliest encounters with mascots, they were never too receptive of me. I was a taller child. I always looked a little older than I was. I don't think I ever got proper attention from those mascots.”

“I really hate the Detroit Pistons' mascot Hooper. A lot of beef with him for a long time. I don't why, he just started going after me. I remember Brook (Lopez, Robin's brother) beat him up and he just started going after me for no reason.”

So the next time you see Lopez fighting with an NBA mascot, it's not all fun and games. It's pretty personal.