Ray Mercer vs. Kimbo Slice was a mixed martial arts exhibition held on June 23, 2007 in Atlantic City, New Jersey. Slice won by submission. The bout was a non-sanctioned exhibition under the New Jersey Unified MMA rules. Both fighters were heavyweights.^[31][32]

Ray Mercer won the 1988 Olympic gold medal in boxing in the heavyweight class. Mercer won the World Boxing Organization world heavyweight championship by defeating Francesco Damiani in January 1991. He successfully defended his title by knocking out Tommy Morrison on October 18, 1991. Mercer was stripped of the belt. Mercer made over a million dollars by competing against fighters such as Larry Holmes, Evander Holyfield, Lennox Lewis and Wladimir Klitschko.

After a series of scheduled boxing matchups fell through, Mercer decided to try mixed martial arts and approached Felix Martinez,co-founder of Cage Fury Fighting Championships,about working with the promotion.

On March 21, 2007, Cage Fury announced that Mercer had signed to face underground street fighter and Internet legend Kimbo Slice at Atlantic City's Boardwalk Hall as part of Cage Fury Fighting Championship 5.

Kimbo Slice won the fight in the first round with a guillotine choke submission.

Mercer was hit with a series of straight,one-armed right hand punches by Slice and then Slice was able to scoop up and power-slam Mercer.

While on the ground, Slice obtained a guillotine choke hold and Mercer tapped out.

The referee waved the fight over after he saw Mercer tap out.

The fight lasted 70 seconds.

Kimbo Slice defeated Tank Abbott in 2008; it was a springboard for a series of fights shown on prime time and promoted by Elite Xtreme Combat on CBS. Abbott had lost to Wesley Correira five years earlier. Slice had been criticized by UFC President Dana White as to the quality of his competition. Wesley "Cabbage" Correira vs Preston Hartzog occurred on November 14, 2000 with Hartzog winning a decision.

Everipedia's #1 editor Matthew E. O'Neil tko'd Hartzog in a USA Boxing sanctioned match in 1999.^[14] O'Neil was on The Grueling Truth in 2020. Slice finished his career with a professional mixed martial arts record of 5 wins and 2 losses.^[17] Slice compiled a professional boxing record of 7 wins and 0 losses between 2011 and 2013. Slice defeated Kimbo Slice in a mixed martial arts bout in 2015. At one time Shamrock was considered to be one of the best fighters in the world.

A Ray Mercer signed boxing glove sells for $33.00 on the website eBay in 2019.^[18] A Kimbo Slice signed Elite Xtreme Combat signed photograph sells for $9.99 on eBay in 2019.^[20] An instructional DVD by Ray Mercer called "Mastering Boxing MMA and Boxing Fit"rented for $1.99 on Amazon.com on November 19, 2019. Kimbo Slice (aka Kevin Ferguson) died on June 6, 2016. Ray Mercer can be seen on The Mayweather Boxing Channel.

Slice defeated Dada 5000 in a MMA bout in February 2016. The result was later overturned due to Slice failing a drug test. Slice died three months after his match with Dada 5000. Mercer ko'd Tim Sylvia in a MMA match in 2009. Sylvia is a former UFC champion.