Germany's famous cross-eyed opossum, Heidi, dies

(CBS/AP) - There are not many animal celebrities in the world, and today there is one less. Heidi, the cross-eyed opossum, whose cute but confused countenance warmed hearts around the world, has passed away.

The Leipzig zoo said Wednesday that the marsupial had been listless and unable to move for several weeks. A decision was made to put the three-and-a-half-year-old animal to sleep following repeated attempts to treat her.

"We carried out every possible test and treatment," zoo director Joerg Junhold said in a statement. "We made the final decision ... to relieve the animal from suffering and pain."

Within minutes of the announcement, Heidi was trending on Twitter and thousands of fans were leaving an outpouring of condolences on her Facebook page.

"How sad," wrote Rene Schaaf, from Heidi's home city of Leipzig. "This lovable creature enriched our daily lives, showing us that 'imperfect' can also be interesting and even beautiful."

Heidi first attracted attention at the end of last year after she was featured on a local television report about the nocturnal enclosure where she spent her final days.

A clip of the report went viral, giving rise to a fan page on Facebook that attracted more than 332,000 admirers from across the globe as well as a wave of Heidi merchandise.

Heidi is the second German animal-celebrity to pass away this year. Fans and animal lovers still have fresh memories of Knut the polar bear, who drowned at the Berlin zoo in March.