If this doesn't look like a D&D creature, I don't know what does. In reality, it's an "aye-aye", a rare species of lemur. But what *could* it be in a world full of magic? You tell me.
Edit: in case the inline image breaks, I've added it as an attachment.
Some kind of monkey that necromancers use as familiars.
Pets for tasloi or forest goblins.
A gargoyle or other animated statue of some sort.
Evil house spirit.
Servants of those creepy elves in the haunted forest.
An elder race whose forbidden knowledge caused their gods to curse them into this form. They scour the world try to keep others from making the same mistake.