There's a predator on the loose. None of us are safe.
I've been trying to get you away from Simba for months!
The wild dog has encountered Timon, Pumbaa, and Simba at some point. It is hinted that he found Timon and Pumbaa to be quite appetizing and has been trying to devour the two friends but they were always rescued by Simba. Therefore, while months passed by, the wild dog has tried to get Timon and Pumbaa away from Simba. Eventually, during his final attempt to separate the three friends, the wild dog disguised himself as a tarsier to trick the duo into thinking that Simba has become a predator.
The tarsier first appears when Timon and Pumbaa come across a skeleton, claiming that there is a predator on the loose. He tells them that he believes Simba is the predator and that they should get away from him, or he'll eat them in their sleep.
He later appears after Timon believes that Simba is definitely the predator and tells him and Pumbaa to come with him to a safe place. This "safe place" is a cave filled with other skeletons where the tarsier reveals himself to be in fact a wild dog and that he has been trying to get Timon and Pumbaa away from Simba for months. He prepares to eat them, but just then, Simba arrives to save them. The wild dog quickly puts back on his tarsier disguise and is picked up by Simba, who throws him far away.
He has the typical appearance of a tarsier: he is short with grayish-brown fur with a cream light-brown chest and bushy end of his tail. He also has purple eyes, a red nose, peach ears and muzzle, and buck teeth.
The tarsier later reveals himself to be a large gray wild dog, perhaps a wolf or a cape dog, with yellow eyes that glow in the dark and a blue nose.
Personality and traits
|“||Tarsier: Your friend, he must be the predator.|
Tarsier: You got to get away from him or I assure you, he will eat you in your sleep. He will, I tell you, he will!
As a tarsier, he seems to be rather pessimistic as he tells Timon and Pumbaa that Simba might be the predator who ate the dead animal, leaving its skeleton lying on the ground. With the tarsier costume off, the wild dog seems to be evil, mean-spirited, cruel, and carnivorous.
The Lion King Wiki has a collection of images and media related to Tarsier.