Revealing mistake: In their efforts to hide Gerald's pet mouse from the hospital staff, Randy and Natalie toss the rodent back and forth and alternate hiding him in their pockets. But every time he's tossed, Devo the Mouse gains weight. In fact, Devo's (stuffed?) stunt-mouse double is at least twice Devo's actual size. (00:27:00)
Continuity mistake: While at the crime scene in the junkyard, Monk is trying to explain things, but is unable to concentrate because one of the stacked junked cars still has a headlight in it. Frustrated, the Captain shoots the light out so Monk can continue, but as the screen pulls back the headlight is still unbroken in the car.