UFC 42: Sudden Impact was a mixed martial arts event held by the Ultimate Fighting Championship on April 25, 2003, at American Airlines Arena in Miami, Florida. The event was broadcast live on pay per view in the United States, and later released on DVD.

UFC 42 was the first UFC event to take place in Florida. Headlining the event was a Welterweight Title bout between Matt Hughes and Sean Sherk. UFC 42 also marked the first UFC appearance of future Middleweight Champion Rich Franklin.

Joe Rogan provided the lead commentary for this event and was joined by colour commentator Phil Baroni with further analysis by Eddie Bravo.

Mark William Calaway (born March 24, 1965) is an American professional wrestler better known by his ring name The Undertaker. He is signed to WWE and is the company's most tenured competitor. Calaway began his wrestling career with World Class Championship Wrestling (WCCW) in 1984. He joined World Championship Wrestling (WCW) as "Mean" Mark Callous in 1989. When WCW did not renew Calaway's contract in 1990, he signed with the World Wrestling Federation in October and, after shortening his name from Kane the Undertaker to simply The Undertaker, has remained with the company since.

The Undertaker has two contrasting personas. The first is the role of The Deadman, an undead, occult-like figure, which has consisted of many different styles. He debuted his original Deadman persona during his own on-camera debut at Survivor Series (1990). At this event, the Undertaker was clad as a Western mortician. Next, in October of 1998, the Undertaker appeared as the leader of the Ministry of Darkness (with similar apparel). Since WrestleMania XX, the Undertaker has appeared as a hybrid version of the Deadman character, using elements of the previous Deadman incarnations.

Benson Henderson (born November 16, 1983) is an American mixed martial artist. He is currently fighting for the Ultimate Fighting Championship and is the current UFC Lightweight Champion. Henderson is known for his aggressive style and his ability to escape from deep submission attempts. As of March 2012, Henderson is ranked as the #1 lightweight fighter in the world by Sherdog.

Henderson was born in Colorado Springs, Colorado to a Korean American mother and an African American father. He was raised in Federal Way, Washington. He attended Decatur High School from 1998 to 2001. Ben became a part of the high school's wrestling team. After graduating from high school, he attended Dana College in Blair, Nebraska and graduated in 2006 with a double major in criminal justice and sociology. While attending Dana College, Henderson was on the wrestling team, and was twice named an NAIA All-American. Henderson is a proud Christian, and uses his fighting to share his beliefs. He is known to quote scripture after bouts, and walks into each fight to a gospel song.

James William "Jim" Ross (born January 3, 1952) is a professional wrestling commentator, referee, restaurateur, occasional wrestler, and former company executive of WWE, where he currently works as a talent relations consultant and on WWE NXT as a Play-by-Play announcer. Ross was inducted into the WWE Hall of Fame in 2007 and is widely regarded as one of the greatest commentators in wrestling history. He is known affectionately by wrestling fans as Good Ol' JR. In recent years, he has developed his own brand of barbecue sauces and cookbooks.

While attending Westville High School, Ross was the first baseman on the Westville baseball team. Ross was a two-time all-conference football player for the Westville Yellowjackets in 1968–69. His maternal grandparents owned a general store in Westville, Oklahoma and his paternal grandfather Dee Ross owned an off-sale beer store and was a carpenter. Ross was also President of the Student Body, a 4 year letterman in basketball, and State Vice President of the Future Farmers of America where he was State Speech Champion in 1968. Ross was also named Honorable Mention on the 1969 High School All State Football team by the Tulsa World as a center.

Diego J. Sanchez (born December 31, 1981) is an American mixed martial artist (MMA) of Mexican descent, with a background in wrestling and Gaidojutsu, system of submission wrestling developed by his longtime trainer Greg Jackson. He currently fights as a welterweight with the Ultimate Fighting Championship (UFC). Sanchez is currently ranked as the #9 welterweight fighter in the world by MMAWeekly.

Sanchez was born in Albuquerque, New Mexico. He attended Del Norte High School, where he became a state champion wrestler.^{[citation needed]}

Diego Sanchez wrestled in New Mexico before starting training MMA while working for UPS. Sanchez eventually joined Jackson's Submission Fighting, still while working for UPS, managing the time between work and training. In 2002, he made his MMA debut for King of the Cage where he also later became a champion.

His UFC debut came when he was chosen as a participant on the first season of the reality show, The Ultimate Fighter. Presented as a young, focused middleweight who only had one goal, to become a UFC champion, he won a contract with the UFC after winning a fight against Kenny Florian, becoming the middleweight winner for the first season of the show. On the show, Sanchez was known for being the "odd-ball" of the group, practicing yoga at odd moments and trying to extract "energy" from a lightning storm, and was also a self-proclaimed "Zen master". Sanchez' last fight before his loss to Josh Koscheck was against Joe Riggs on December 13, 2006 at UFC Fight Night 7. Sanchez landed a right hook that knocked Riggs down, followed by a running knee that knocked Riggs out. Sanchez won at 1:45 of the first round, scoring the first UFC knockout of his career.