Professor MacKrill

The marine biologist Professor H. O. MacKrill graduated from the University of Copenhagen and is voiced by Terry Jones. He hypothosises that eventually humans will cause such global warming that the polar ice caps will melt and flood the Earth, so he's invented "Fish Potion" which will enable humans to turn themselves into fish and thus continue to inhabit the planet. Having the foresight to come up with an antidote was just a bonus.