While at the post office mailing a letter to her pen-pal, Lilo finds experiment 509 pod. Jumba reveals it is an extraterritorial weed that grows out of control, bent on destruction. He deems too dangerous and locks away in a draw. Later, Lilo bets Myrtle that she can win the orchid competition. No one will help her grow a real orchid, so she steals experiment 509, gets it wet, then plants it in a pot with a big dose of super grow for plants. Meanwhile, Stitch trains to ride in the rodeo and Pleakly enters his "Pi-normous," a human-size pineapple. At the competition, Experiment 509 grows to be massive, destroying Pleakly's entry and disrupting the festivities. Lilo and Stitch work together along with Stitch's rodeo completion to get 509 under control and find it's one true home.