Polaris

Polaris, "The Bear Cub" is a Silver Key Celestial Spirit that is under a contract with Yukino Aguria

Appearance
Polaris is a very large spirit that has the appearance of a bear standing on its two hind legs. His body is composed of pink mechanical body parts with exception of his blue eyes and tan-colored snout. Each of Polaris' limbs end with five long claws and he sports a yellow handkerchief around his neck.

Eclipse Celestial Spirits arc
Polaris is summoned by Yukino while facing Eclipse Mother Pisces, who comes rushing read to take a bite out of his body. He stops her by putting his large arms on her teeth but she sends him flying away with a smack of her tail fins. Seeing this Yukino powers up Polaris, leading him to consume some honey and activating Mighty Bear. However, Mother Pisces tells him that good boys take a nap after lunch, causing Polaris to go to sleep.

Magic and Abilities
Immortality: As a Celestial Spirit, Polaris cannot die, unless he is somehow forced to stay in the Human World.

Enhanced Strength: Polaris' large size enables him to rely on his strength, something confirmed by Yukino saying that when it comes to power Polaris won't lose.

Mighty Bear: By a command from his contractor, Polaris produces a jar of honey from an opening in his stomach which he then consumes, powering him up. It is unknown how much power this grants him as he fell asleep after using this.