The Price of Healthy Gums Is Eternal Vigilance - S2-E6
Revealing mistake: When Alan is banging on the bathroom door, the entire set is shaking.
Can You Eat Human Flesh With Wooden Teeth? - S2-E16
Revealing mistake: When driving back after leaving Jake in the rain, the rain that settles on the bonnet of the car starts to pool. On a moving car this doesn't happen. Therefore you can tell the car wasn't moving. (00:09:20)
Does This Smell Funny to You? - S2-E24
Revealing mistake: At the start, Jake is writing the end of his report in class. However, watch closely and his pencil isn't on the paper. (00:00:25)
Frankenstein and the Horny Villagers - S2-E8
Revealing mistake: Alan slams his bedroom door shut when Judith has turned up. When he does the wall wobbles. (00:06:50)
Last Chance to See Those Tattoos - S2-E11
Revealing mistake: Charlie is typing away on his computer. But he is tapping the same 3 keys. (00:09:45)
Revealing mistake: When Alan is wrestling on the floor with the naked lady you can hear her voice perfectly clearly despite her mouth being covered with a towel and being face down. (00:02:15)
Revealing mistake: When Charlie is shaving at the start, he's not actually touching the skin with the razor. (00:00:05)
Answer: That would be "Corey's Been Dead For an Hour" in season 4, episode 9.
Super Grover ★