Teddy Roosevelt opted not to shoot a bear that someone caught for him to shoot (because it would have been like shooting fish in a barrel; iirc the bear was immobilised). The press at the time got hold of this story, turned it into a story about pity/mercy (neither applied, the bear was killed anyway, just not by getting shot by Roosevelt) and an enterprising individual made a toy based on it, which became more popular than expected.

The popularity of the toy was also a boost to Roosevelt's popularity, which is why at least one presidential candidate at the time tried to get something similar going for himself, but possums just aren't cuddly and a copy of a popular thing rarely manages to reach the heights of popularity the thing it tries to copy got.