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 playing the role of Sauron from Primal Rage. The colors on this Tiny are lighter and more cartoony than seen in Meet the Robinsons.