Plue

Nikora, "The Canis Minor", is a Celestial Spirit that has no obvious combat abilities and is stated to usually be used as a pet for low powered wizards. Lucy Heartfilia seems to use hers, named Plue, as merely a comical character for his summoner. Nikora keys are shown to have been sold for as little as 19,000 Jewel.

Appearance
Plue is a short, stout white creature (who is commonly referred to as a dog by Lucy Heartfilia) with bland eyes and a golden horn-like nose. He cannot speak besides saying Plue, but Natsu can understand what he is saying. He mostly communicates by using gestures and motions which makes Lucy think he's cute.

Personality
He loves sweets. He can only be summoned on Tuesdays, Wednesdays and Thursdays when Lucy makes her contract with him. But later, Plue could be summoned everyday. He serves as a cute pet for Lucy rather than a combat spirit.

Synopsis
Plue's role in the story is much like a pet for Lucy. However, he was used to demonstrate how contracts are made to Natsu Dragneel. He also seemed to recognize Loke, during the Loke arc, which was possibly meant to foreshadow Loke's revelation as a Celestial Spirit, or nothing.

Plue had also been summoned by Lucy to trick enemies. These include Sherry during the Galuna Island arc and one of Daphne's creatures (anime only). When battling Sherry, who was able to control Lucy's spirits, Lucy deliberately summoned Plue, knowing Sherry would control him. Once controlled, "evil" appeared on his forehead and he is seen with glowing eyes running aggressively towards Lucy. However, his attacks didn't harm Lucy one bit, leaving Sherry confused. Released from Sherry's control, Plue immediately apologized to Lucy.

In the Daphne arc, Lizardmen were attacking Erza and Lucy. Realising those Lizardmen could mimic the skills and abilities of their opponents, Lucy summoned Plue, changing the Lizardman she was fighting to a similar size. Plue then started to dance, gradually gaining speed. The Lizardman started to mimic his moves, but was unable to keep up with Plue, and soon vanished defeated.

Trivia

 * Her quote when summoning him is: "Open a Gate of the Canis Minor! Nikora!", as seen in the Chapter 4, when she first summons him.
 * Apparently, it was his idea for Natsu to make a team.
 * Nikora is the only "dog" Happy likes.
 * In chapter 71 Happy plays a trick on Lucy by feigning a voice for Plue. Happy makes a reference to Rave Master.
 * Mirajane believes that Plue is the strongest among all of the Celestial Spirits.
 * A special restriction made by Hiro Mashima stated that the number of lines on Plue's nose must be 5, no more, no less.
 * Plue gets very wrinkly in hot water.
 * the name of his constellation is Canis minor the little dog.