Cancer

Cancer, The Giant Crab, is a Celestial Spirit that is summoned by Lucy Heartfilia.

Appearance
Cancer looks like a funky hairdresser. His hair are red and braided in cornrows. He always wears a blue shirt and dark trousers with a ring chain. Color of his eyes is unknown because Cancer always were sunglasses.

Personality
Cancer has a very "cool" personality, he isn't very emotional or hotheaded.

Happy first thought, Cancer would end his sentences with the word -kani (crab); however, Cancer actually says -ebi (shrimp) at the end of his sentences. This shocked and displeased Happy. In the anime Cancer acts differently when in the presence of Erza. He acts in a gentlemanly manner and ends his sentence with -choki, meaning snip instead of -ebi. In ep 6 Erza made this suggestion. Her "not abolishing the opposition" and strict personality made a giant impression on Cancer that he even gave her a flowers during the Galuna Island arc.

History
Currently is unknown when and where Lucy gained his Key. She has it from beginning of the series.

Daybreak arc
Cancer is first summoned to fight Duke Everlue, however he thinks he is being summoned to give Lucy a haircut. After the confusion ended, Cancer helps Natsu Dragneel defeat him by cutting off what is left of Everlue's hair and mustache.

Lullaby arc
Seen in the anime but not the manga, Lucy summons Cancer to get rid of the remaining Eisenwald members ( and also to make a good impression on Erza). It is shown that his scissors are sharp enough to cut through weapons such as swords and hammers.

Galuna Island arc
Seen in the anime only, Lucy summons Cancer again to battle the Moon Drip worshipers. He seems to have gotten a small crush on Erza since the Lullaby arc, as he presented her with roses before following Lucy's orders, much to Lucy's chagrin.

Tower of Heaven arc
Cancer is briefly used to defeat some tower guards by giving them bald haircuts. He also provides Lucy with new clothes from the Spirit World. In the Anime, Lucy summons Virgo to fight instead.

Fighting Festival arc
Cancer is briefly used by Lucy, along with Taurus and Sagittarius, to stop the Naked Mummy Guild from robbing the Merchant Guild in Acalypha. Once again he defeats the dark guild members by giving them bald haircuts.

Edolas arc
Cancer is briefly used to cut Lucy Ashley's hair, and asked her that she really want this, because in Earthland girls doesn't do that too often.

Magic and Abilities
Scissors: Cancer is Lucy's hairdresser because of his weapon which seem to be two large pair of scissors which he can also use to cut hair. Lucy uses Cancer to cut her hair or make a new hair style for her or her enemies.

Trivia

 * Her quote when summoning him is: "Open the Gate of the Crab! Cancer!", as seen in the Chapter 7, when she first summons him.
 * Cancer can be summoned on Tuesday, Thursday, Saturday, and Sunday.
 * Cancer maybe be Lucy's first or second Celestial Spirit, seeing as when she made the contract with Taurus she had already two gold keys.