Dr. Goosewing and Mr. Duck

S1, E22: Von Goosewing is, as usual, hovering over Castle Duckula trying to find some way to obliterate Duckula and broods on his inability to do so, but as he is about to take a sip of some coffee, actually drinks from his patented carpet stain remover. This has a surprising effect on the drinker; it will turn them into the reverse of what they are for a short time. Von Goosewing then comes to the conclusion that he can get Duckula to take this chemical so as to neutralize him long enough to eliminate him, and he plans to put it in Duckula's milk. Needless to say, chaos soon ensues and virtually everyone in the castle takes this potion.