Miyu Miyu (ミユ・ミユ?, Miyu Miyu) is the Nandaba family cat. He is 12 years old, overweight and has a rather lazy, cranky personality. Haruko Haruhara uses him to communicate with her superiors. The Galactic Space Police Brotherhood appear to also use him as a video camera, watching Haruko and Naota Nandaba cautiously. He also returns briefly in the opening montage of episode 4 of FLCL Progressive.
Miyu Miyu is very lazy when Haruko's superiors aren't using him. He seems to find the interaction between Haruko and Naota amusing. In episode 2, when Takkun tried to play with him, Miyu Miyu ignored him and simply sat down, something which he does for most of the series. His actions and reactions are very reminiscent of slapstick comedy characters in many cases.
Miyu Miyu has grayish-blue fur, likely because of old age, and white paws and underbelly. From his left eye always being partially closed to his short, scraggly tail to the jagged outer edges of his ears, his body heavily suggests he was attacked or injured. His cheeks droop like jowls and he has exactly 12 whiskers, above his eyes and on his cheeks in groups of three respectively. He walks around with a bell on his neck, likely to warn the others of his presence, though it doesn't ring when he does move. Despite his apparent obesity, in episode 4, he is shown to be very fast and agile, running in a panic with Naota to the bathroom.
The Galactic Space Police Brotherhood use him as a cell phone of a sort to communicate with Haruko. As shown in episode 5, Haruko may have to move him around to get a good signal. The Brotherhood also uses Miyu Miyu to inflict physical damage on Haruko, as shown in episode 2 after Naota's rant.
In episode 2, Miyu Miyu actually speaks to Haruko, saying, "Which part is really the truth...Meow?" and "We're talking about you...Meow." This is done during Naota's rant, so it can't be said if it really happened or not. Since Miyu Miyu is seen talking to Haruko afterwards, however, it's likely that it actually happened.
In the opening sequence of LooPQR, Miyu Miyu is sitting on a parked scooter as Hidomi prances through Mabase. Being controlled by her Cat Ear-Shaped Headphones so she only experiences happiness, she turns around after passing him and barks at him like a dog for fun, scaring him off of his perch.
- The Newtype USA section on Miyu Miyu claims his voice actor is "???" and is left as "?" in the Japanese credits
- This same section's interview reveals that Miyu Miyu's left eye being partially closed is based on a stray cat director Yoshiyuki Sadamoto fed during his school days, and that he is also supposed to resemble Doraemon from the manga of the same name.
- Due to his age in FLCL and the adulthood of Commander Amarao's son in Progressive, Miyu Miyu could very well be over thirty years of age. However, his appearance and reaction to Hidomi doesn't show it.