Destination Moon: Part 2 - S3-E10
Deliberate mistake: The shot of the plane landing in Syldavia at the start of the episode, after the recap of part one, is merely the exact same shot of the plane landing in Syldavia at the start of the previous episode. Note the vehicles on the ground are completely identical and the plane, as well as its movements are also identical. (00:25:00)
Chosen answer: It is a pill that makes alcohol taste disgusting.