Snufkin is present in many of the Moomin books, but he first appears in Comet in Moominland (1946). In the book, young Moomintroll and his friend Sniff set off to the Lonely Mountains as mysterious signs start to appear of a strange star with a tail.

Is Snufkin a human?

In Moominpappa's Memoirs, however, it is revealed that he is the son of the Joxter and Mymble, who are an interspecies couple. This very likely means that Snufkin is a hybrid.

Does Moomin have a tail?

One day Moomin notices that his tail seems to be thinning. ... Finally Moominmamma cooks up a magic potion, and it works like a charm, but now Moomin's lustrous new tail is, well, solid gold! Moomin becomes the toast of society, and the target of numerous journalists and money-making schemes.