For the season finale, the trio discuss virtual reality, holidays and happiness. Plus an extraordinarily rare event takes place... 

The trio discuss major modern artworks, Karl talks about a tricycle-riding woman from his estate. Karl and Ricky go head to head on the act of whistling.

Karl recounts having eaten a beetle, having been lost in London and having talked to a ghost in Cornwall, plus his theory on how Martians are more productive than humans - a must watch!

Karl discusses his childhood memories of having thousands of Tic Tacs in his house, plus his curiosity at the reading material in a doctor's surgery. 

Topics include the value of discovering new species; a perturbing feature for a future car; and a documentary about a pregnant man.

Karl's academic predictions for the future include; everyone will be ugly and physically weaker, trousers will cease to be produced and we will blend all of our food.

Karl ponders height extremes when he learns that one of his new fans is actor Warwick Davis. Stephen entertains us with a story of his wild night out clubbing with his friends in London.

Karl talks about having been rushed to hospital. He says that kidney stones were found and he had a catheter put into his penis. Karl ponders a phenomenon; Karl's diary; and more.

Karl shares his thoughts on why insects are so deserving of his attention. Karl talks about his disappointment when learning about a killer octopus; what he would change in crabs; more stuff about insects. Karl's diary is also mostly about insects.

Ricky gives Karl some animal facts. Karl ponders the question of whether you control your brain, or your brain controls you. From Karl's diary we investigate the curious case of the invisible Chinese man, why blind people have affairs, the feasibility and usefulness of putting a mirror on the Moon, and birthdays.

The trio discuss animals and diseases; evolution; a fly that is supposedly a pet; Karl's diary.

Karl discusses what his doppelganger would be like. Ricky gives Karl a riddle. Karl and Stephen say what they do not like about Ricky's cat. Stephen discusses his holiday in Rio, where he went for Carnival.

Karl tells Ricky and Stephen about his pitch of a movie starring "Clive Warren" and Rebecca De Mornay. Stephen reads more pages from Karl's diary, revealing Karl's dislike of camping in Australia and his habit of saving insects from falling into a swimming pool.