text: In Land of Black Gold, the detectives mistakenly swallow some mysterious pills used to adulterate fuel, that causes them to sprout immensely long beards and hair that change colour constantly and grow at a break-neck pace. The condition wears off by the end of this adventure, but it relapses in Explorers on the Moon, causing problems when Captain Haddock must continuously cut their hair, repeatedly switching back to re-cut floor length hair (and mustaches and beards) which all grow back in seconds. Frustrated at this, the captain exclaims "After all this, when they ask me what did I do on the rocket, I'll reply 'Me, you say? I was the barber!'"
  In the 19 books following Cigars of the Pharaoh, Thomson and Thompson appear in 17 of them, not appearing in Tintin in Tibet or Flight 714 to Sydney. In some of these books their role is minor – the duo's appearance in The Shooting Star is confined to two panels; they appear briefly only at the beginning of The Broken Ear (before being tricked into closing the case in the belief that the stolen object has been returned when it was actually replaced by a fake); and are imprisoned and face execution on false charges in Tintin and the Picaros. During their other appearances, they serve as the official investigators into whatever crimes Tintin is currently investigating. Their final appearance was in Tintin and Alph-Art.