CHARLOTTE, N.C. — If any of Ron Rivera's players have been holding a grudge, they had a chance to get even with him at Tuesday morning's practice. 

Rivera was egged by six Carolina Panthers as part of the #CrackCancer challenge to fight pediatric cancer. The players "helping" Rivera complete the challenge were Greg Olsen, Luke Kuechly, Christian McCaffrey, Kawann Short, Trai Turner and Shaq Thompson. 

Olsen went first, much to his delight.

"I've been wanting to do this, coach, for nine years," Olsen said before slamming an egg on Rivera's head. 

His technique was widely criticized by the group when the egg busted and mostly missed Rivera's head. 

"You've got to slam it," one of the others said. "Set the tone!"

Rivera was challenged to be egged by NFL reporter Peter Schrager. He tweeted a video of his challenge and nominated NFL coaches John Harbaugh, Sean McDermott and Pat Shurmur. 

Crack Cancer is a challenge that supports fundraising efforts of the Willie Strong Foundation throughout May, which is Brain Cancer Awareness Month. Similar to the ALS ice bucket challenge, people are challenged to get egged then post the video on social media using #crackcancer and then donating to the Crack Cancer. 

Also at that practice, McCaffrey had an 11-year-old Panthers fan shadowing him via the Make-A-Wish Foundation.

You can find more information about the Willie Strong Foundation and Crack Cancer by clicking here.