In Monsters University, Randall was originally a kind, timid teenage monster who would hang out with Mike. However, after Mike was forced to befriend Sulley and stopped associating with Randall, he felt hurt and this caused him to slowly turn on Mike and become his new enemy, even though he betrayed Mike in the first place.
In Monsters, Inc., Randall is greedy, ruthless, sneaky, short-tempered, competitive, and overall evil in nature. As well, Randall is something of a selfish jerk who doesn't care about a lot of people. Judging by his intentions to capture children for their screams (and possibly never return them), he is probably willing to severely harm little kids (or worse).
In Monsters University, Randall is seen as a young, freckle-faced teenager. He sometimes wears his purple glasses but stops wearing them near the end of the film.
In Monsters, Inc., Randall has 3 fronds, green eyes, 4 arms and legs, and has the ability to completely blend in with his surroundings, making him invisible (as well as being able to cling to walls). He can also camouflage similar to the way chameleons are misconceived to.
In Monsters, Inc., Randall is Mike and Sulley's direct rival and nemesis. He is able to harness his invisibility at will, as seen when he used it to scare Mike in the locker room. He is shown to be in competition with Sulley and Mike for the glorious post of Top Scarer. He also managed to beat Sulley and become the Top Scarer, although the victory was short-lived when Sulley managed to scare an entire slumber party and regain his spot seconds later. He then furiously threatens to put Fungus into the shredder if he doesn't bring him a new door in 5 seconds. However, Randall has also constructed a "Scream Extractor", and attempts to kidnap a human child in cooperation with the company's leader, Henry J. Waternoose, with the hope of eventually rising to the leadership of the company.
However, this plot failed when Sulley was sent by Mike after closing hours to recover paperwork (which Mike forgot to turn in) and stumbled upon the kid, whom Sulley nicknamed Boo. He eventually deduced Mikey as being involved in Boo's release into the Monster World and attempted to manipulate him into bringing the child to him, only for this to backfire when Mike accidentally got himself captured trying to convince Sully that Randall wasn't up to something. Largely because Sulley witnessed Randall going in, they initially thought he was trying to "cheat" at the scare record, although after his accidental capture of Mike, he makes clear that his plans didn't even involve winning the scare record, let alone cheating at it. After Mike and Sulley are exiled, Randall and Waternoose go through with testing the scream extractor on Boo (although Waternoose expresses distaste for having to exile Sulley and Mike due to Randall's negligence, as well as pointing out that Sulley was "twice the scarer Randall could ever be"). After Sulley manages to escape and wreck the Scream Extractor, Randall then attacks Sulley and tries to strangle him. He proves to be quite an adversary, due to his chameleon-like abilities. However, when Mike gets annoyed with the fact that Sulley is not listening to his apology, he throws a snowball at him, hitting Randall instead: allowing Mike to realize that Randall has been attacking Sulley.
Randall then gave pursuit and had them cornered at the Scare Floor, although Celia, after learning the truth from Mike, aided them by "awarding" Randall with the all-time Scare Record (although Randall was too determined to stop Sulley and Mike to care about his "victory"). He goes after the trio in a chase through the factory until he manages to grab Boo and escape into an activated door. When Sulley comes to rescue her, Randall surprises him and attempts to send him falling from the door, lamenting of how Sulley was always the best Scarer and with him gone, Randall will finally come on top. Suddenly, Boo begins to pull on his frond and hits him with a baseball bat, making him turn different colors, then Sulley restrains him with a chokehold, followed by a snake wrestling maneuver.
Afterward, he gets thrown through an active door, while desperately begging them not to do it, that banishes him to a trailer home in the middle of a swamp in the south, where a Cajun family beats Randall senseless with a shovel, thinking that he is a gator. The door then has its glass light shattered and is then tipped over the railing it was leaning against and shatters on the floor far below, thus ensuring that Randall cannot return through the door.
In the prequel, Randall (nicknamed "Randy") is first seen when Mike arrives in his new room, as Randall is his roommate. The two greet each other, and Randall seems nice, offering Mike first choice of the beds. Randall shows that he has the power to turn invisible, doing so when surprised, leaving only his glasses hovering in mid-air. Mike suggests that he should use that power when scaring, to Randall's surprise. He soon follows Mike's advice of getting rid of his glasses because they don't disappear whenever he turns invisible. Even though the two become great friends, Randall is worried about school and wonders if he'll manage to impress the cool kids, but Mike reassures him. He follows Mike and sits next to him on their first day of class.
Later, while Mike is studying scaring, Randall decided to bake cupcakes for a party organized by the cool kids, decorating them to spell "Be My Pal". At the party, Randall tries to offer cupcakes to some girls, but Mike runs into him while riding Archie the Scare Pig, splattering all the cupcakes on Randall, which spell "lame," with the letters on them, much to his dismay.
He is later seen helping Mike study by asking him questions on phobias (such as arachnophobia, fear of spiders). However, Randall ends up slowly decreasing his friendship with Mike when he replaces Sulley as a member of Roar Omega Roar and thus was unable to help Mike and join Oozma Kappa as their sixth member since he's finally in with the "cool kids". His friendship with Mike decreased further when Randall took part in his group's prank on Mike's team, Oozma Kappa.
After this, he is frequently seen in group shots of the Roar Omega Roar until the final event of the Scare Games, where he faces off against Sulley. Randall is poised to scare, when the vibrations from Sulley's roar, cause him to fall on a carpet and involuntarily blend in with its pink and heart pattern, causing his scare score to be minimal, resulting in his former "friends" berating him and kicking him out. After this, he looks over bitterly at Sulley and mumbles his last line in the film, "That's the last time I lose to you, Sullivan!"
Because of this, Randall assumedly begins his gradual descent into villainy as his jealousy for Sulley grows over the years. Because of his hatred for Sulley, he also comes to no longer accept Mike as well, but not for the same reason. Randall seems to hate Mike by the time Monsters, Inc. happens, not because of anything that he personally did to him, like Sulley, but simply because of Mike's close association with him.
During the credits, Randall appears on one of the Scare Cards, eventually becoming a Scarer at Monsters, Inc.
Randall, as a secondary antagonist, eventually found his way back to Monstropolis using the door system and survived his encounter with the hillbillies. As part of his revenge against Mike and Sulley, he tried to frame Mike for stealing the other monsters' comedy props. After Mike has been sent to prison, Randall strikes again trying to frame Sulley for assault on Waxford when he visits him in the security camera room to look at the tapes of the locker room. The fight makes its way to the Laugh Floor where after being unable to hit Randall, Sulley succeeds in exposing him by pulling the fire alarm. Randall is sent to monster prison afterward and Mike's name is cleared. Later, Randall would be freed by Sid Phillips (who had visited the Monster World earlier) alongside Mr. Waternoose and the three would together work on another revenge plot. They cut off the door power when Mike and Sulley return from a visit to Boo's and try to figure out how to go about their revenge. Randall turns down Waternoose's idea of a frame job and Sid just wants his reward of being given the door system patents to become rich in the human world. Eventually, Celia and Boo escape when Boo activates her door and the three villains give chase while shutting Mike and Sulley out of it. Going to the neighbor's house, all three try to capture them, but Celia and Boo make it to the resident child's closet and bring the three right to a CDA task force waiting to take them into custody. It is unknown if Randall ever got released, though there is an extremely small chance.
Randall squints because he isn't wearing his glasses. However, he usually prefers not to wear them because his stealth ability does not hide the glasses.
Randall has a nephew named Rex.
In earlier drafts, Randall's original names were "Switt" and "Ned". He was named "Ned" in the early treatment, and "Switt" in the original opening.
In another deleted scene, another name for Randall was "Switch".
In an early script for the film in place of Fungus, Mike Wazowski was going to be Randall's assistant instead.
Randall shares the same first name and many traits of Randall Weems from the Disney television series Recess. Both characters are sneaky, mean, and tend to assume similarly serpent-like postures.
Randall's nephew, Rex (named after the Toy Story character), made an appearance in the "Monsters Inc. Storybook Collection" as one of the toddlers in the company's daycare program. It is unknown whether Rex has the surname Boggs or not, but is often referred to as "Randall's nephew". Rex looks like his uncle - including Randall's ability to "disappear" - but has orange scales and only one frond, as opposed to Randall's purple scales and three fronds.
In several video games set after Monsters, Inc., Randall now appears to be back at work and is no longer depicted as evil. Instead, he has apparently reformed but is still extremely devious and sneaky.
In the prequel, Monsters University, Randall appears to be wearing glasses, while in the original he doesn't. This is due to the fact that Randall learns that he cannot make clothing invisible, such as glasses, and discards them. This also explains why he is seen squinting in Monsters, Inc. since he cannot see well without glasses.
One of the backgrounds Fungus used to demonstrate Randall's cloaking abilities is the cloud background that served as the wallpaper of Andy's bedroom in the first Davis residence seen in the first Toy Story film.
At one point, Randall angrily threatens to "personally put [Fungus] through the shredder" if he doesn't get him another door immediately. This is a reference to Steve Buscemi's character, Carl Showalter, from the 1996 crime film Fargo, who was killed and put through a wood chipper (shredding his body to pieces).
In the movie Monsters Inc., Randall makes a possible reference to his defeat at the Scare Games when he attacks Sulley and says, "You don't know how long I wanted to do that, Sullivan!"
The color schemes Randall underwent after being hit by Boo before Sulley grabs him and throws him into the hillbilly trailer door include pale yellow with red zigzag lines, blue with purple spots (Sulley's own color scheme), pink and yellow plaid, white with red stars, a shade of dark turquoise, a red brick pattern, green and yellow swirls, red and black plaid, blue with white spots, purple with a brown head, purple with white stripes, a red circle pattern, and finally solid green.
When his skin gets a heart pattern in the Scare Games final, one of the hearts is where his nose would be if he had one.
According to the M.U. website, Randall had very little control over his camouflaging abilities as a kid. Though MU the movie does not go into detail on this fact, it can be assumed that between the events of M.U. and M.I., Randall had learned to assume near perfect control over his abilities.
Above Randall's bed in Monsters University is a framed inspirational poster with the words "The Winds of Change: Can you hear them?" printed. This is a reference to his infamous quote from the first movie.
Randall serves as the host of the PC game "Pinball Panic", which came as a bonus disc with select copies of the Monsters, Inc. 2-disc Collector's Edition DVD.