Tiny is a Tyrannosaurus that was brought under the control of the Mini-Doris that was remotely controlled by Bowler Hat Guy, who got the idea when seeing the Mini-Doris hovering over a dinosaur topiary on the grounds of Anderson Observatory. Wanting to keep it a surprise, he didn't inform Doris, who was planning on cutting the chandelier to get rid of Wilbur, and was enraged by the blatantly obvious attack as opposed to her subtle actions. After a fight with the family and Bowler Hat Guy again being told by a controlled minion that his plans weren't thought through, the Tyrannosaurus is freed from Mini-Doris control when Wilbur shoots it off his head with Gaston's Meatball Canon and turns out to be a rather docile specimen and is shown to be acting like a puppy. Even after Doris' actions are undone by the climax of the film and he should have been sent back as a result, Tiny still appears to see Lewis back off to the past, now a pet of the Robinson household.
Tiny makes a cameo appearance in the 2012 animated film Wreck-It Ralph as a video game dinosaur in Game Central Station, heavily resembling Sauron from Primal Rage. The colors on this Tiny are lighter and more cartoony than in Meet The Robinsons.