Randy and Howard want to win a science fair, but things don't go as planned.
Randy fights a robot, smokebombs to temporarily escape from it, and enters the NinjaNomicon in order to get help. He uses the chain-sickle but failed, then used a shovel on the robot and won. He finds the fart box and keeps it to show Howard later. In science class, Mrs. Driscoll tells Randy and Howard that they'll fail science class unless they win the science fair. Meanwhile, Marci McFist suggests that McFist and Bash work together on Bash's science project. Neither are up to the idea, though, and McFist just has Viceroy build a machine for Bash. Back at Randy's room, Randy shows Howard the fart box, and Howard played with it the whole night. He used the Fart Box in the Norrisville High Science Fair in order to pass science. However, Mrs. Driscoll gave him and Howard an F for it.
The title is an allusion to the 1978 comedy horror film Attack of the Killer Tomatoes.
The mutated potatoes in this episode are similar to the Phineas and Ferb episode "Lotsa Latkes" where the potatoes were also mutated by accident.
Bash complains that Mrs. Driscoll doesn't know how to count to C, a reference to Randy's math book having the title Math: Easy as 1-2-C.
A background joke in this episode consists of many of the science projects having a name beginning with "Our Friend the ..." with the final word increasing in absurdity with each new shot, including "Our Friend the Potato," "Our Friend the Tree," "Our Friend the Log," "Our Friend the Changing Room," (into which Randy dodges to change into the Ninja), "Our Friend the Sheet Rock," "Our Friend the Priceless Oil Painting," and "Our Friend the Pane of Sheet Glass."
The last two mock the convention in action movies to have objects such as paintings and panes of glass shattered in the course of a fight or chase scene; in a clever subversion, neither is damaged in Randy's robot fight here.
One of the science projects is an ant-farm under the title "ANTZ." This may be a reference to the 1998 DreamWorks animated film of the same name, the first full-length animated feature released under the DreamWorks label.