Hell Is That Noise: The Code 991 noise, which is disconcerting in general, becomes a special source of Nightmare Fuel after the CHOMP. It's popular among fans as a phone alarm since they know the stress response it causes will force them to act.
Memetic Badass: Ikaruga is the pinnacle of YAMATO DAMASHII. He's "so Japanese that he's more Japanese than all of Japan and its lands and Shinto deities combined; people look at him and see the General of Generals, while BETA burst into flames just by being near him."
age's Engrish in Alternative and other related works, along with the quote "English can eat shit. I repeat, English can eat shit."
One-Scene Wonder: For all his popularity, Ikaruga only appears during one very short scene that isn't even really about him.
The Scrappy: Naoya Sagiri is not a popular character in the fandom, to say the least. The reasons for this largely revolve around his behavior during the coup arc and his behavior back in the world of Extra where he come across as extremely selfish.