Popular parody anime like Gintama and Lucky Star are famous for their anime parodies, but even more serious series like Genshiken have included characters cosplaying their favorite anime. Due to Japanese copyright laws, many in-universe anime cosplays are parodied or off-branded to avoid litigation or legal trouble.
But sometimes, anime are able to get away with direct references to other series without too much trouble. Whether it's a thinly veiled parody of another famous anime or a legitimate homage to a popular series, there are plenty of otaku anime characters who dress up like other anime characters.
10 Kanako Ohno Uses Her Appearance To Her Advantage (Genshiken)
An incorrigible yaoi fangirl who's especially fond of balding middle-aged men, Kanako Ohno has a devotion to cosplay that leads to her cosplaying a multitude of characters. With her long hair and attractive figure, Kanako can have her pick of the litter when choosing characters to cosplay as. In Genshiken: Second Generation, Kanako is spotted cosplaying as sweets-loving Stocking Anarchy from Panty & Stocking w/ Garterbelt while she's attending ComiFes with her American friends. She's also seen cosplaying Homura Akemi from Puella Magi Madoka Magica during the same event.
9 Patricia Martin Cosplayed As Mikuru Asahina (Lucky Star)
Lucky Star is a series that's famous for its otaku culture and jokes, and Patricia Martin is one of the series' best tropes. Patricia (or "Patty" for short) is an American foreign exchange student who loves manga and anime to the point that she sometimes equates it to Japanese society in general. One episode of Lucky Star shows Patty working in a cosplay café while dressed as Mikuru Asahina from The Melancholy of Haruhi Suzumiya. Notably, she's cosplaying a version of Mikuru that's dressed in combat waitress cosplay from her original series.
8 Sakata Gintoki Infamously Cosplays Several Shonen Jump Characters (Gintama)
Gintama is lovingly referred to as the king of parody anime, and it's a well-deserved title. Gintama mostly focuses on parody and humor, including making jokes about anime itself. Sakata Gintoki and the rest of Yorozuya's employees have cosplayed several characters from Shonen Jump anime, among others.
Yamcha from Dragon Ball Z and Luffy from One Piece are two popular shonen characters that Gintoki dressed up as. The Yorozuya crew has also been spotted dressed as Neon Genesis Evangelion characters and Naruto characters, and Gintoki has also parodied JoJo's Bizarre Adventure.
7 Angela Burton Is An American Otaku Who Loves Cosplay (Genshiken)
One of Kanako's friends from the United States, Angela Burton starts visiting Japan every year to cosplay with Kanako during the ComiFes anime convention. She's an energetic and athletic girl who's got the stamina to take cosplay pictures for hours on end. Although she doesn't speak Japanese, she's shown to have a basic understanding of the language in the series. In Genshiken: Second Generation, Angela is seen cosplaying alongside Kanako as Panty Anarchy from Panty & Stocking w/ Garterbelt as well as Mami Tomoe from Puella Magi Madoka Magica.
6 Hanako Koyanagi Specializes In Boy's Love Cosplays (Wotakoi)
Although it's not entirely clear which characters she's cosplaying in Wotakoi: Love is Hard for Otaku, it's obvious that Hanako Koyanagi has a flair for cosplay that's hard to beat. Hanako goes to great lengths to use chest binders, makeup, and wigs to transform her feminine image into a handsome bishonen straight from a boy's love series. Hanako is so convincing in her male cosplay that other characters (including her boyfriend, Taro Kabakura) are impressed to know she has such a well-endowed bust while dressed in her normal clothing.
5 Koro-sensei Dresses As Human Characters Despite Not Being Human (Assassination Classroom)
Assassination Classroom is another series that's famous for its various parodies, and anime parodies are certainly on this series' list. Koro-sensei has completely dressed up as Goku from Dragon Ball Z, and he's sported hairstyles and accessories of other anime characters as well. Naruto Uzumaki's Kotonoha ninja headband from Naruto and Monkey D. Luffy's iconic straw hat from One Piece are two examples of accessories that Korosensei has worn. And, in a tribute to Gintama, which once showed Gintoki parodying Koro-sensei, Koro-sensei is also seen dressed as Shinsuke Takasugi from Gintama.
4 Susanna Hopkins Accompanies Kanako & Angela At ComiFes (Genshiken)
Another incurable otaku from America, Susanna Hopkins (or "Sue," as she's often called) goes to ComiFes with her friends Kanako and Angela every year. Unlike Angela, Sue has moved to Japan for university, so she doesn't need to deal with a pesky international flight.
In Genshiken: Second Generation, Sue cosplays Kyubey from Puella Magi Madoka Magica alongside Kanako's Homura and Angela's Mami. Later in the series, she's also seen cosplaying the Princess of the Crystal from Mawaru Penguindrum. Notably, Sue has the habit of responding to others with various quotes from anime characters.
3 The Matsuno Brothers Cosplay Several Anime Characters (Mr. Osomatsu)
Yet another parody anime, Mr. Osomatsu is the continuation of the 1960's series Osomatsu-kun and features the eponymous Osomatsu Matsuno and his brothers as adults. Like many parody anime, the Matsuno brothers riff on popular social trends, including popular anime. The first episode of Mr. Osomatsu has actually been banned for its egregious use of parody. Each of the brothers dresses up as new generation anime characters in a bid to win over new fans. At one point, Jyushimatsu Matsuno is seen wearing a Honoka Kosaka wig and the second-year Otonokizaka school uniform from Love Live! School Idol Project.
2 Konata Izumi Cosplays Haruhi Suzumiya Alongside Patty (Lucky Star)
Unsurprisingly, Patty is not the only character in Lucky Star who loves anime and otaku culture. Konata Izumi is introduced far before Patty makes an appearance in the anime, and Konata makes herself known as a proud otaku quite quickly. Konata appears cosplaying as the selfish Haruhi Suzumiya from The Melancholy of Haruhi Suzumiya in the same scene that Patty is seen dressed as Mikuru. There's even a third unnamed character dressed as Yuki Nagato to complete the set. It's worth mentioning that both Konata and Haruhi are voiced by the same voice actress in both their respective English and Japanese dubs.
1 Kenjiro Hato Crossplays At Least One Female Character (Genshiken)
Although he's first introduced as a woman in Genshiken: Second Generation, it's revealed that Hato is a boy who's fond of yaoi and boy's love series. He created a female persona to better fit in with other yaoi and boy's love fans, who typically tend to be women. Since he crafted such an impeccable persona, it's no surprise that Hato also decides to cosplay female characters. In Episode 7, he's seen cosplaying as Laura Bodewig from Infinite Stratos. Later in the episode, Kanako comments that she also had Hato fitted for a Madoka Kaname cosplay from Puella Magi Madoka Magica.