Foster's Home for Imaginary Friends - Season 0 Episode 16

It's Bloo's birthday, and his cake is being guarded by Mr. Herriman. After being refused to have his cake, Bloo leaves and Frankie comes in and sees Mr. Herriman sleeping on the job. She makes it look like he ate the cake in his sleep and leaves. Mr. Herriman soon wakes up and notices this and thinks he indeed ate the cake, at which point Frankie is yelling for Bloo to come into the kitchen, as they both enter, Frankie sees the cake is gone and scolds Bloo for it and threatens to kick him out. Feeling guilty, Mr. Herriman confesses that he ate the cake, on which both Frankie and Bloo begin to laugh, saying they pulled a prank on him and that the cake is just fine. When Frankie opens the refrigerator to show that the cake is fine, it actually is gone, having been taken by Madame Foster.