Right after Kuroyukihime reveals her true form, she asks Haru to take her flying. He is obviously flustered and nervous, and Kuroyukihime is openly flirting with him. What makes this so funny is that we get a shot of Taku looking at them, obviously enjoying their little scene.
Shenanigans that occur when the Black and Red kings stay for the night in Haruyuki's apartment. All of them, other than the few bits that were heart-warming instead, beginning from Kuroyukihime's attempted departure.
In episode 9, Haruyuki and Kuroyukihime enter his apartment to find Yuniko playing his (rather gory) video games. The look on poor Haru's face is priceless. The scene is made even funnier in the English dub, in which the first thing that greets Haru when he opens the door is Yuniko yelling, "DIE, SUCKERS! BURN IN HELL!"
A double one happens during the fight against Yellow Radio's forces. Haru, being a metal type that conducts electricity, is easily incapacitated by an electricity-wielding opponent... until Kuroyukihime reminds him to ground himself, literally by digging his hand into the ground. He does so and the attacker's generator promptly shorts out.
When Chiyu and Kuroyukihime win the first set against Haru and Taku in the two-on-two tennis match in the manga, Kuroyukihime accuses the guys of holding back. In Taku's case, it turns out to be the result of a well-intentioned but misguided desire for Chiyu to win. Haru, on the other hand, doesn't want to admit that he's distracted by the hem of the shorter skirt that Kuroyukihime's avatar is wearing.
When Kuroyukihime tells Haru that she'd give him anything he wants as a reward for defending their legion territory, the first thing that comes to Haru's mind is friggin' food.
Shortly after Chiyu gets her duel avatar, Lime Bell, she gets into a duel with Haru to test her powers, with Taku watchng as a spectator. Lime Bell charges her special attack gauge and tries to use it on Haru, only for nothing to happen. Cyan Pile then has Lime Bell beat up Silver Crow in order to charge it up enough to try again.
The second ending. Kuroyukihime fighting her net avatar over Haru, and ultimately delivering a One-Hit KO with the latter's parasol.
Early on in Volume 4, Sugeno, the guidance counselor, calls Haruyuki in to interrogate him about the camera in the shower. He starts off with a highly misguided attempt to sympathize with Haru.
Sugeno: Arita. The truth is, I might look like this now, but back when I was in school, I wasn't all that popular with the girls. Haruyuki: Huh? Sugeno: It's true. I was on the judo team, see? I used to be so jealous of the guys on the soccer team. They had one girlfriend after another. Haruyuki: (thinking) What he just said is totally not okay in at least four different ways. I mean, he's saying he looks hot now, no one in judo can get a girlfriend, everyone in soccer is a playboy, and on top of that, he's assuming girls don't like me.note Haru does concede Sugeno has a point about the latter, but both of them clearly underestimate Haru's appeal to the opposite sex.
When Silver Crow confirms his metal armor has cold resistance, Scarlet Rain decides to test this for herself by pouncing on his back and assaulting him with snowballs from the Snow and Ice stage. And if that wasn't funny enough, her gleeful facial expressions just sell the scene.
Episode 21. Taku apologizes to Haru, but since the apology is conveyed through Neurospeak, he and Haru end up being Mistaken for Gay when he takes Haru's hands.
In episode 24 Haru asks Kuroyukihime to "be with him forever". This causes Kuroyukihime to absolutelyfreakout. Haru doesn't understand her reaction until he figures out how it came across, and immediately gets flustered.
Before that, when Haru comes up to Kuroyukihime after she gets off her train, Megumi visibly has Glowing Eyes of Doom, from jealousy.
In the first OVA, while Taku and Haru implement the plan to take out Pumpkin-Chan, Taku attacks it with a water gun. Haru goes full Rambo in his pig avatar...Taku's look is priceless.
In the second OVA, the main cast has a mixed bathing session at a public bath as their duel avatars. Chiyu needles Taku over his disappointment over the latter part.
In Volume 5, Fuko shows up at the worst possible time while Haruyuki's having Kuroyukihime over and gets jealous... of Haruyuki.
In Volume 6, Utai tells Haruyuki that she's nervous about the prospect of her former fellow Nega Nebulus member Fuko coming over, and Haruyuki wonders whether it's because they don't get along. When they do meet, Fuuko glomps Utai so hard she has trouble typing out her messages.
In Volume 9, The Reveal of Ash Roller's true identity- a timid schoolgirl with a speech impediment. There's a reason why Ash Roller is so different from Rin in the real world, but the disconnect between their personalities is hilarious.
In Volume 9, during Haru's first duel with Ash Roller after learning that his true identity is and is not a girl named Rin(long story), Haru calls him by his real first name, forgetting that Rin isn't controlling him at the moment. Ash Roller then goes ballistic over Haru calling his sister by his first name, saying that it's too soon for first or even second names.
In Volume 13, after Haru decides not to tell Utai about Aqua Current coming back to Nega Nebulus, they have a conversation about Utai's new title. which Kuroyukihime apparently made official.
Haru: Um, thats a secret for a little longer. Utai: Even for me, the Super President of the Animal Care Club? Haru: Th-thats just a title I-Izeki went and gave you. Utai: Sacchi revisedI mean, correctedthe club register and changed my role to to School Cultural Exchange Student and Super President. So it's an official job now! Haru: Wh-what?! (thinking) Shes gone and done something serious for fun again.
When the protagonists stop by Sky Raker's hideaway in the Unlimited Neural Field, which she hasn't been to in roughly two years, she says that she has some food inside the fridge, but warns that it's two millennia out of date.
Chiyu not only uses the "-chan" honorificnote An affectionate and diminutive honorific often used on young girls. on Scarlet Rain's real name, but even goes so far as to call Metatron, a God-Class enemy, "Metacchi."
As Haru's delivering a heartfelt monologue about his friendships, Kuroyukihime tries to interrupt him twice, and he realizes that he accidentally put his hand on her butt. He recoils in shock, but it turns out that Kuroyukihime wanted to say something to him.
At the start of the mission on the Unlimited Neural Field, Ash Roller lands on Silver Crow with his bike, angry about Haru accidentally feeling up Kuroyukihime in front of Rin. Silver Crow ends up Giving Up the Ghost.
As Scarlet Rain rams through obstacles in order to charge her special attack gauge, she cheerfully warns her passengers as though a tour guide would.
After Blue Knight performs a Big Damn Heroes moment with the members of the Blue, Yellow and Purple Legions, Black Lotus calls him out on not helping against Nyx earlier. He tries to play it off by delivering a cool line about heroes showing up late, which results in Black Lotus having Cross-Popping Veins.