The Seagull has seen many text and music banned for good reasons. For example, the national anthem was banned at the Tian'anmen Square following the massacre in 1989. The Communist Party's own L'Internationale was also banned, because after all it was a fighting song. Numbers such as 64 or square of 8 can be seen as suggestive, understandably so.
However, the official Xinhua News Agency banned a picture which they themselves rated as a best picture of the year, a picture showing a dog catching a (explicit!) Frisbee disc: http://news.china.com/zh_cn/hd/11127798/20121228/17606576_12.html (click). To be specific, the picture was snapped on June 16, in Budapest in Hungarian. The thumbnail still exist, but the original picture had gone. All other pictures in this series, including those immediately next to it still are viable. In place of the large size photo, a 'China.com' logo was displayed indicating a broken link.
It can be more bizarre than banning a dog catching a Frisbee....
..but it happened after the chief editor of official Global Times Mr. Hu Xijin was mocked as a good dog who could always make up a rational for the Party no matter how unreasonable the Party might appear. They say, no matter how far or low the Party throw a Frisbee, Mr. Hu can always catch it. PS: in Chinese culture, a dog is not a positive reference for a person.
Power to the Online Chinese citizens, who made the dog catching Frisbee a taboo.