Ika Musume

Ika Musume is the titular main protagonist of the Squid Girl anime and manga.

Ika an anthropomorphic squid-girl who comes ashore to invade the surface world in retaliation for constant human pollution of the seas, only to end up being forced to work as a waitress at the Lemon Beach House restaurant in order to pay for a damaged wall of the restaurant.

Appearance
Ika Musume is humanoid squid girl with a petite frame, a blue waist-length cephalopod tentacles for hair and has blue eyes.

Ika wears a white sleeveless tunic that went past her knees with blue lining designs and circles, white shoes with blue cuffs, blue bracelets and a white hat shaped like a squid's head.

Personality
Although generally immature and often getting herself into mischief, she is a fast learner, able to master complex things such as math and other languages in a short period of time.

She's shown to be extremely good at math, has mastered several skills that have nothing to do with world domination, and of course there's her extremely powerful tentacles.

Her favorite food is shrimp, and she greatly fears natural predators of squids like sharks and killer whales to the point that even swimming floats of such creatures terrify her.

Abilities
She possesses numerous squid abilities including extending her tentacles, regenerating severed ones, spewing squid ink from her mouth, glowing in the dark like the firefly squid, swimming and breathing underwater. She also has bracelets that enable her to have weight-shifting abilities.

Trivia

 * Her dress is not an ordinary one, with at least 2 known features:
 * Auto-repair in 15 minutes: after being ripped by protruding wire-mesh fence and torn in half by Eiko.
 * Non-sticky/instant dry: After a car splashes roadside puddle, Squid Girl simply dusts it off. After she sits on a chair with wet paint, she simply peels the paint away.
 * Also, while not exactly a "feature", when she went tanning while wearing her dress, her dress "tanned" while her skin remained the same tone.
 * Squid Girl is quite similar to Sgt.Keroro of the Sgt.Frog series, as both are characters plan to invade Earth for a reason (Sgt.Frog invades Earth/Pekopon to relay information to the awaiting Keron Invasion Army whereas Squid Girl invades Earth because humans are polluting the oceans), both ended up as a slave after they did something bad (i.e., damaging property), and both characters ended up befriending a human but decided to use them as part of their so-called "invasion plans". Both often have crazy misadventures while trying to "invade" Earth.
 * In the drama CD, Squid Girl is shown to have the ability to break any material (such as glass) with ultrasonic resonance.
 * In the dub for Season 2, Christine Marie Cabanos was the only voice talent to come back as her role.