|Air date||December 3, 2009|
|Previous episode||Bagpipe Buddy|
|Next episode||Lock Out|
Supersize Timmy is the fourty-ninth episode of Shaun the Sheep.
When the Flock are peacefully eating grass, Timmy hears the Farmer planting his vegetables, and he also sees the Farmer putting Miracle Grow Fertiliser (Fertiliser that can make things become giant) on a tomato, but when he sees nothing happening, he puts more on the tomato, but nothing happens, so he takes a break, but while he's not looking, the tomato grows! Timmy eats the tomato, and he grows into a gargantuan, which scares a duck away, and the Flock! Shaun and the Flock run up a tree, and Timmy shakes the tree to get the Flock out, until his Mother comes and Timmy jumps and squishes her, not knowing he's a gargantuan! Bitzer then comes out and sees the giant Timmy, and screams and jumps inside the house, nailing wooden planks on the door. Bitzer then looks out the window, and goes tell the Farmer and takes him outside. Shaun sees Timmy pushing the tractor into the Sheep Dip, and he also sees Bitzer and the Farmer, so he hides Timmy somewhere. The Farmer doesn't see Timmy, so he goes back inside, and Bitzer sees that Shaun hid Timmy in the garden shed! Bitzer tries to tell the Farmer, but he doesn't believe Bitzer as Timmy grabs Bitzer and sees the duck on the roof and climbs up the house. Bitzer sees the Farmer in the bathroom and he tries to tell the Farmer about Timmy, but he can't hear Bitzer. Timmy tries to grab the duck and Bitzer faints since he's afraid of heights (as an example of King Kong) but Timmy's Mother squeaks Timmy's teddy and Timmy jumps off the roof and Bitzer snaps out of it. Timmy gets sleepy holding his teddy and he decides to go in the barn, but breaks the fence, which wakes up the Farmer! Timmy goes inside the barn, but bangs his head, and cries! The Farmer comes outside and sees the tree knocked down, the tractor in the Sheep Dip, and he also sees his garden destroyed! The Farmer then sees the door rumbling from Timmy's crying, and he thinks there's a monster in the barn! The Farmer runs to hide and call the town, but as he runs, it is shown that the tomato from earlier shrunk back to it's normal size. That night, the townsfolk come to the farm to kill the monster, and as Timmy is still crying, his tummy rumbles, and as the Farmer and the townsfolk are just about to come in the barn, Timmy farts so loud that he shrinks back to his normal size, and the townsfolk leave angry thinking they've been tricked, with the Farmer trying to convince them that there was a monster. As Shaun, Bitzer, Timmy, and his Mother come out to get away from the yucky smell, they hear a loud quack, and they see the duck from earlier ate Miracle Grow Fertiliser, and is on a rampage! Shaun then laughs as the episode ends.