Stolen Drinker - Banksy

In March 2004, a ten-foot statue was erected in central London. It was called ‘The Drinker’ and based on Rodin’s ‘The Thinker’, except with a traffic cone placed on its head. The only giveaway to its creator – a stencil on the plinth that said ‘Banksy’.
And then it disappeared. Not under cover of darkness, nor by council workers claiming health and safety, but by a gang of masked thieves with a flatbed truck. Later, a reporter from a national newspaper received a ransom note from ‘art terrorist AK47', whose aim it was “to poke two fingers up at the art world, where everyone’s busy blowing smoke up each other’s arses, and terrorise people with humor“.
AK47 (a Kalashnikov assault rifle, but AK als stands for 'Art Kieda') demanded a £5,000 ransom. Banksy offered £2 and the deal was refused. Three years on, and thieves have got into AK47's garden in Hackney and taken the statue, leaving the plinth and cone.
AK47 accused Banksy, or "his people", of being behind the theft. "If Banksy has got it back, I will treat it as a joke. But if it's someone taking it for its financial value I'd be annoyed."

Sources:
Huffington Post
Meet the Art Terrorsit AK47
But Is It Kidnap?
A Recreation of a Stolen Banksy Sculpture
Daily Mail