The Japanese company Sanrio, which holds the rights to the Mr Men and Little Miss characters created by the late Roger Hargreaves, says it may take legal action against a British company selling sick versions of its characters.
Until this morning online retailer Orbital Panda offered T-shirts featuring one of the most famous characters, Mister Bump, with dynamite strapped to his bandages and the slogan "Mr Jihad".
Although the company appear to have removed the item it is still available from other retailers, as are a fridge magnet, cufflinks and other items.
Another character, "Miss Jihad", featuring a girl carrying dynamite, is available as a fridge magnet.
Hargreaves, who died in 1988, created the first of 49 Mr Men books in 1971. The Little Miss series, which started in 1981, ran to 42 books. Not all the books are available in English. Over 85 million have been sold around the world in around 20 languages.
Following the death of Mr Hargreaves his widow Christine sold the rights to Chorion in 2004, which sold them to Sanrio in 2011.
Sanrio says the items infringe intellectual property rights, telling The Sun: "The Mr Jihad and Miss Jihad products were created without authorisation."
Sanrio also own the rights to the Hello Kitty range. Yesterday it emerged that an anti-Isis commander in Syria called Zahran Alloush released a video on YouTube in which he commands Muslims to crush Isis. However the rebel's tough stance and harsh words are somewhat diminished by the fact he is speaking in close proximity to a pink Hello Kitty notebook.
The Mr Jihad and Miss Jihad items are the latest example of Jihad chic: Isis T-shirts and hoodies openly on sale in Istanbul and then on Facebook. Taliban and Hamas T-shirts are also available, as is an Isis figurine.
Despite having a range of views apparently hostile to Western counter-cultural beliefs militant Islam is seen by some as being cool and anti-establishment, which may be one reason why so many young people seem keen to join the struggle.