Tintin and the Picaros: Part 2 - S2-E9
Other mistake: A monkey throws a bottle of whiskey from a tree which then lands on Haddock's head. When they show the bottle on Haddock's head, the bottle is shown stuck to his head, but there is nothing there actually making the bottle stick. (00:25:35)
Tintin and the Picaros: Part 2 - S2-E9
Other mistake: When Haddock is in the lake, he is sinking, struggling to stay above the water and the water is even going up to his neck area. Tintin then goes into the lake to fetch Haddock and then stands in the exact same area where Haddock is up to his neck in the water, but the water only goes as far as Tintin's knees. (00:26:40)
Chosen answer: It is a pill that makes alcohol taste disgusting.