: While never officially confirmed in the sketches, notes suggest that Endaddine Akass was intended to be Tintin's longtime nemesis, Rastapopoulos , in disguise. The Unfinished Ending The book ends on a literal and metaphorical cliffhanger.
: Created by fictional sculptor Ramó Nash, this art style consists of large plastic letters. Captain Haddock, under the influence of Bianca Castafiore, even purchases a giant Perspex "H". Tintin and Alph-Art (The Adventures of Tintin 24)
Unlike the globe-trotting adventures typical of the series, this story is primarily set within the Brussels modern art scene. : While never officially confirmed in the sketches,