The aye-aye (Daubentonia madagascariensis) is a long-fingered lemur, a strepsirrhine primate native to Madagascar with rodent-like teeth that perpetually grow[4] and a special thin middle finger.

Among the aye-aye's signature traits are its fingers.[24] The third finger, which is much thinner than the others, is used for tapping, while the fourth finger, the longest, is used for pulling grubs and insects out of trees, using the hooked nail.[15] The skinny middle finger is unique in the animal kingdom in that it possesses a ball-and-socket metacarpophalangeal joint.[29] The aye-aye has also evolved a sixth digit, a pseudothumb, to aid in gripping.[30]

Unfortunately endangered:

The aye-aye was thought to be extinct in 1933, but was rediscovered in 1957. Nine individuals were transported to Nosy Mangabe, an island near Maroantsetra off eastern Madagascar, in 1966.[38] Recent research shows the aye-aye is more widespread than was previously thought, but its conservation status was changed to endangered in 2014.[1][2] This is for three main reasons: the aye-aye is considered evil, the forests of Madagascar are being destroyed, and the farmers will kill aye-ayes to protect their crops and for poaching. However, there is no direct evidence to suggest aye-ayes pose any legitimate threat to crops and therefore are killed based on superstition.[39]

https://en.wikipedia.org/wiki/Aye-aye