|Behind the scenes|
|First Appearance:||The Calculus Affair|
|Last Appearance:||Tintin and the Picaros|
In The Calculus Affair, Sponsz masterminds the kidnapping of Professor Calculus in an attempt to obtain the plans for Calculus's sound weapon. He flirts with Bianca Castafiore after her opera recital, inadvertantly allowing Tintin and Captain Haddock, hiding in Castafiore's wardrobe, to steal papers from his overcoat, allowing Calculus's release.
Sponsz bears the thwarting of his kidnap plan as a "bitter humiliation" and in Tintin and the Picaros, he uses his country's military links with San Theodoros to have Castafiore and the Thompsons arrested in order to lure Tintin into a trap. At the end of Tintin and the Picaros, Sponsz is sent, not willingly, back to Borduria.
Sponsz is an unquestioning devotee of his country's dictator Marshal Kûrvi-Tasch. He is a calculating and ruthless figure, and bears strong grudges against those who upset his machinations.
Sponsz is based on a Belgian slang word meaning '"sponge." In Tintin and the Picaros, the San Theodorans call Sponsz "Esponja."
Harry Thompson claims Sponsz is based on Paul Remi, Herge's younger brother (on whom Tintin is also based). Sponsz and Tintin both have buzz-cut with central quiff hairstyles. It could be said that Sponsz gives an idea to what Tintin might look like when he is older.