Rex

Rex is a large green plastic Tyrannosaurus Rex in Disney/Pixar's 1995 film Toy Story and its 1999-2010 sequels in the saga. He also makes his cameo from the 2001 film Monsters, Inc. during the end credits. Rex is the fourth most popular and recognizable character from the Toy Story franchise after Buzz, Woody and Jessie. He is voiced by Wallace Shawn.

Personality
Despite being played with as a ferocious Tyrannosaurus Rex, Rex is gentle, kind, and hates any kind of argument or confrontation. He lacks intelligence, and is extremely trusting and usually enthusiastic about anything and everything. His greatest fear is that he will be replaced or abandoned. With his childlike demeanor, and lack of self-confidence, Rex is the most innocent of all the toys, and shows the greatest desire to be loved and played with. He also has a fear of other dinosaurs, but this is eventually overcome.

Toy Story
In the beginning of the film, Rex attempts to try out his roar to Woody after luring him there by stealing his notepad. He learns to his dismay that the roar he emitted did not even come close to scaring Woody, and in fact it actually came off as annoying. He is also shocked along with the toys when he learns that Andy's "Birthday" was moved from the Wednesday of the following week to the current day, and expresses fear of his being replaced, especially if it was another carnivore-based dinosaur toy as he wouldn't take that rejection well. When the surprise present is unveiled to the kids and Sarge reports it, but is unable to ascertain the identity of the present, Rex ends up inadvertently wrecking the baby monitor due to his shaking the bedside due to impatiently wanting to know the identity of the surprise present. When Buzz Lightyear first came to Andy's room, he was just as amazed by him as all the other toys (as well as greatly relieved that Buzz wasn't another dinosaur) and even managed to become more fierce with his roar thanks to Buzz.

Rex tries to avoid confronting Woody when he is accused of trying to jealously kill Buzz (although mostly because he doesn't want confrontation from either side), but slowly and reluctantly turns against him under peer pressure, quickly experiencing guilt later on. He is known to have a queasy stomach and actually threw up when he saw Buzz's severed arm.

By the end of the film, he seems to have gained confidence throughout the movies, expressing hope that Andy will receive a leaf-eating dinosaur for Christmas that Rex can play with and intimidate.

Toy Story 2
At the beginning of Toy Story 2, he is playing the "Buzz Lightyear: Attack on Zurg" video game, which terminates with Buzz being destroyed by Emperor Zurg, much to Rex's frustration. Nevertheless, thinking he is all prepared with his video game experiences, Rex accompanies Buzz, Potato Head, Hamm, and Slinky on their mission to rescue Woody after he is stolen by Al McWhiggin of Al's Toy Barn.

After the toys enter Al's Toy Barn, Rex excitedly finds a "Buzz Lightyear" video game strategy guide, and claims it's nothing short of extortion that the game is unbeatable without the guide. He is responsible for the crash of the car as he blocks Tour Guide Barbie's view with the booklet, losing the booklet as a result. He also attracts Buzz #2 with his claim of knowing how to defeat Zurg.

Rex is considered to be the heaviest of Andy's toys when he loses his grip on the new Buzz's utility belt line and pushes the toys to the bottom, causing the new Buzz's strength to give out. Later, Buzz #2 and the toys use Rex's head as a battering ram to break into Al's apartment. When the toys go down the elevator after Al leaves the room with Woody and the Roundup gang, he witnesses the duel between Buzz #2 and an Emperor Zurg action figure. When Zurg is about to finish Buzz #2 off (at point blank range), he turns away, not bearing to look anymore, but his tail lashes out and knocks Zurg down the elevator shaft, making him feel overjoyed about finally defeating Zurg.

At the end when Hamm is playing the video game, he asks Rex for help, but Rex proudly replies, "I don't need to play it; I've lived it!"

Toy Story 3
In the third film, Rex eagerly awaits the opportunity to finally get played with by children again. In the opening scene of the film, he reprises one of his roles from the first film while Andy is playing with him as the giant dinosaur that eats forcefield dogs. Years later, Andy is 17 years old and Rex, like the other toys, wishes so much to be played with that he even gets excited when Andy picks him up. The toys are accidentally almost thrown away and believing that they are just junk to Andy now, decide to sneak into Andy's mom's donation to Sunnyside Daycare box.

Once at Sunnyside, they are welcomed by the other toys that reside there, led by the Strawberry scented bear, Lotso, who show that Sunnyside is a paradise for toys where you will be played with by generations and generations of kids. The toys there take Rex and the others to the Caterpillar Room, telling them that they will soon be played with by children. When the kids are returning to the room, Rex eagerly waits in front of the door, excited that he's finally going to get some play time. However, when the kids enter, it is discovered that they are very little children who have no regard for treating a toy right, even pulling off Rex's tail. When the toys try to complain to Lotso, it is revealed that they were sent to the Caterpillar Room to be beat on by the toddlers on purpose and that you have to earn joining the Butterfly Room. Lotso even reprograms Buzz so that he's back to being a senseless astronaut who keeps Rex and the toys in shelved baskets (which function as prison cells).

When approaching the incinerator, Rex mistakes it for daylight. He joins hands with the other toys, specifically Hamm and Slinky, as they prepare for incineration. Along with all the other toys, Rex is saved by the Squeeze Toys Aliens with a giant crane. Rex joins the other toys in returning home to Andy. In the end credits, it is shown that he has become great friends with the Triceratops toy Trixie (ironically fulfilling his dream of meeting a herbivore from the first movie).

Monsters, Inc.
Rex makes a cameo during the credits of the film auditioning for the role of Ted, but Rex was soon dismissed and replaced by a giant chicken.

WALL-E
Rex makes a cameo as a toy in the beginning when WALL-E opens his truck.

Origin
Rex is based on the Tyrannosaurus toy from the Dinoriders toyline. In a blooper of Toy Story 2, the toys use him as a battering ram, only for Rex to hurt his head when banged against the locked grate. Rex makes a cameo in a blooper of Monsters, Inc. where he waits at the crosswalk with Mike and Sulley who both are smaller than him. Rex is a playable character on the Toy Story Racer Video Game.

Disney Parks
Besides parade, Rex does not truly make any appearances in the parks. In Disney's Hollywood Studios, he can be seen in the Pixar Play Parade as well as a mini game alongside Trixie in Toy Story Mania which can also be found in Disney California Adventure at the Disneyland Resort, Despite not making many appearances live, Rex is often seen in a large variety of merchandise.

Aside from the actual parks, Rex plays a major role in the musical stage adaption of the film on board the Disney Cruise Line.

Trivia

 * In Toy Story on Ice, Rex has a wife named Mrs. Rex.
 * Rex is shown to be left-handed. This was shown when meeting Buzz in Toy Story, he shakes Buzz's left hand.
 * Rex quotes a few of George McFly's lines from Back to the Future: "I don't like confrontations!" and "I don't think I could take that kind of rejection!".
 * Rex makes a cameo in the outtakes for Monsters, Inc. where he tries out for the role of Ted.
 * A Rex toy appears at the beginning of WALL-E for a brief second when WALL-E is opening the door of his truck. Since it's a close-up, it can be very easy to spot.
 * According to the official movie magazine for Toy Story 3, Andrew Stanton is credited for the final design of Rex's face in the original film.
 * In the first film, Rex states that he was made by a subsidiary of Mattel (coincidentally, real-life Rex toys are now made by Mattel and Thinkway).
 * While inside Al's Toy Barn in Toy Story 2, Rex appears in a rearview mirror (viewed by Mr. Potato Head) as he tries to catch up with the car, parodying a scene from Jurassic Park where a Tyrannosaurus Rex appears in a rear-view mirror when chasing a crew in a jeep (although for entirely different reasons as the T-Rex in the film was trying to eat the crew in the car, while Rex was attempting to get back in the car). Coincidentally, Rex's mature roar is a duplicate or resemblance of the T-Rex in Jurassic Park.
 * Real-life Rex toys used to be made by Hasbro, but as of 2009, are indeed made by Mattel.
 * Along with the Aliens, Rex is the only main character to not use an angry expression in "Alive" mode.
 * In Toy Story 3, when he appears out of the ground, he roared with the Jurassic Park T-Rex's roar, which is the same roar Dim made to scare Thumper away in A Bug's Life.
 * Rex shows symptoms of neurosis in all three movies. This problem is somewhat addressed to this in the 2012 animated short Partysaurus Rex.
 * Rex, despite being a toy Tyrannosaurus rex, actually has three fingers on each hand instead of two in real life. However, this may have been intentional since Rex is a toy dinosaur, which unless it was sold at a science museum gift shop or made for educational purposes, is actually not meant to be accurate.