Whenever a girl meets one of the Ninja turtles she is either shocked or surprised and becomes his love at first sight, but that did not happen to a female Salamandrian alien named Y'gythgba.
Even though two hated each other, Y'gythgba begins to get interested in Raphael during their brawl against each other and Raphael didn't get interested into her until she hits him really hard. A hit that he really liked and it felt nice too. Since then both of them can't stop thinking about each other, while Raphael admits to his friends that he does like the Lizard girl, however Y'gythgba keeps denying to her Commander about her feelings for Raphael. After saving her from ice dragons proving he is not her enemy, she returns his feelings. After saving her, both introduce themselves but Raphael has troubling pronouncing Y'gythgba's name. So, he asks her if can call her Mona Lisa, after his admiration of the painting of the most beautiful woman (at the same time calling Y'gythgba beautiful).Thus making Mona Lisa flattered and lets him call her that.
In the ship Raphael tries to tell how he feels about Mona Lisa but she says it for him in her language. It is unknown what Raph wanted to say "I really like you or I love you" to her. After saying his feelings for; Mona and Raph share their first kiss.
After their first interaction with each other both can't stop thinking about each other. And whenever Raphael and Mona Lisa see each other again they would go into their own little world.
During Raphael's space adventure, he and Mona Lisa had been sending intergalactic love mail and (is possible that Raphael may have gotten Mona Lisa's email address before their departure from Dimension X) thus making Raphael & Mona Lisa fans wondering what both characters have been writing or videoing about, possibly about their personal life and secrets.
In episode "The Evil of Dregg" it is revealed by a hurt Raphael that he really trusts Mona Lisa more than his family and his friends or he might meant other space aliens.
Even though Raphael was angry at Mona Lisa for her betrayal, Raph still loves her and becomes really upset after Mona Lisa told the Turtles to get back to their ship and leave as she and the Commander stay behind to stop Dregg. But before she faces the enemies, she tells Raphael that she will always love him. After witnessing Mona Lisa getting stabbed in the back by the scorpinoid; Raphael becomes furious, upset and attacks Dregg single handedly. After defeating him Raphael runs and screams out to Mona Lisa in concerned. Holding her and ignores the scorpinoid. Raphael forgives Mona Lisa. As Both Raphael and Mona Lisa share a kiss.
After their space mission is over and Raph finishing telling stories about his trip including meeting Mona Lisa. Since than he never mentions about her again at the same time he shows to his family and friends that he doesn't miss her. As usual he tries to show his tough guy role.
Mona Lisa is mentioned in the episode "Insecta Trifecta" due to Raphael's phobia of bugs has brought up is being "over" and snapped at Donnie for keep bringing up the past about Mona Lisa thing on Dregg's planet as Raphael angrily tells them all to just drop the whole thing already. It is shown that during his bug phobia hallucinations, Mona Lisa and begin to appear them symbolizing that he's still slightly hurt on that day by her "betrayal" but at the same time it also shows that deep down he really misses her very much.
In the episode "The Tale of Tiger Claw", Raphael mentions Mona Lisa as he picks up Chompy and he telling him about the new woman mutant at the same time he says "but she's No Mona Lisa", showing that he's still loves Mona Lisa.
Mona Lisa returns in S5 ep5 "When Worlds collide", as she and the commander are heading towards earth. after hearing the name of the planet, Mona Lisa realized that it's the same planet that Raphael lives on and begins to daydream about him doing pushups and gets lost for a few seconds. Raphael is seen lonely as all of his brothers are spending time with his crush but than he gets a call from Mona Lisa. Through his space helmet and is seen very happy. As Mona Lisa's ship landed and steps out of the ship Raphael is seen happy and runs towards her, it look like they were going to hold hands like they did before but Raphael hugs her instead as well as she did too. During the mission to lure the Newtralizer, Raphael "propose" Mona Lisa to stay on earth but responded she has a very important job as dedicated to battle and honor for her people.
During the invasion of Dregg, Bishop comment on Mona Lisa and her commander for their stupidity for leading dregg to earth (though it was an accident) Raphael tries to defend Mona Lisa but she defends herself and Raphael is shown to be scared after her threat towards Bishop.
After defeating both enemies, the salamanders were about to leave but Mona Lisa asks permission to stay on earth and to protect it from future threats (wants to be with Raphael), he lets her stay on earth.
Both Raphael and Mona Lisa hug each other and Raphael tells Mona Lisa if she liked to join the mutanimals team and she accepts it. The episode ends with Raphael and Mona Lisa hugging and forming a heart. They are now an official couple.
- Mona Lisa will be voiced by Zelda Williams in the 2012 series. Whom is the daughter of the late Robin Williams.
- Mona Lisa stays on earth with Raphael and has joined the Mighty Mutanimals.
- However some fans of this relationship are either confused or upset for why they didn't put her with the main group.
- It is possible that both Mona Lisa and Raphael are still too young to be"living" together.
- It is unknown if Mona Lisa will appear in episode 14 of TMNT 87 crossover story arc, as it revealed that the turtles need the Mighty Mutanimals for help and the last three episodes of the season as it takes place in the future, when the characters are adults.
- Fans of Mona Lisa want her to returned to the CGI series. Since so many of the 1987's characters are returning.
- It has been hinted that Mona Lisa's age that she is eighteen or nineteen years old same age as: April and Karai.
- If Mona Lisa does return in the CGI series, she'll have to wear clothing due to her being a female.
- There's an art of both Mona Lisa and Raphael (Mona Lisa in her 80's version and Raphael in his 2012 appearance) in anime style created by a Snafu comics member Bleedman, hoping that she will return in the CGI series.
- There have been some references of Mona Lisa in the 2012 series:
- In episode Battle for New York, when Kurtzman is showing a slide show of the Kraang's secret weapon at the time he accidentally shows a picture of a female mutant lizard wearing Kurtzman's clothing, and was posing for him, thus making Raphael gasping in attraction.
- Some fans believed that this clue means she might appear in the CGI series. So far this reference only started to appear in season three alone.
- If Mona Lisa does appear in the 2012 series, she might appear in season 4, the same season that her 1987's self counterpart appeared.
- Mona Lisa will be the second girl to actually return one of the main turtles feelings, the first is Renet.
- Y'Gythgba is the second girl to kiss one of the turtles on the first day they meet, the first is Renet.
- Raphael is the first one out of the four turtles to get a girlfriend.
- Mona Lisa might be the key for Raphael's temper problem. Whenever Raphael is with Mona Lisa he channels his emotion on love rather than on rage.
- On the left side on Mona Lisa's head one of her spots is in the shape of a heart.
- Mona Lisa is the fifth girl to have multiple guys attracted to her, the other four are: April,Tang shen, Karai, and Renet. So, far She has attracted Raphael and Mikey (It is unknown is Leo and Donnie feel the same way like Mikey)
- Some fans believed that a background teen girl with short blond hair, who wears a pink head band, a purple top and a purple plaid dress is Mona Lisa herself.
- Raphael is the one whom gives Y'gythba's new nickname, instead of Mikey which for the first time he is fine with it.
- There have been rumors that Raphael and Mona Lisa will be dancing together in a future episode.
- Mona Lisa appears to sashay when she walks.
- Mona Lisa will not be a mutant or human in the 2012 series.
- A fan posted some of the pages from Step into Reading #2 book: Alien Attack. It shows some of Mona Lisa's interaction with Raphael.
- There have been theories about Mona Lisa might be related to or may had a relationship with once to The Newtralizer. It's been revealed in EP 5 of S5 that both Salamandrians don't know each other at all.
- According to Ciro, Mona Lisa's real name in the 2012 series is gonna be Y'gythgba.
- Mona Lisa is the only love interest of one of the Turtles who is not human or human hybrid.
- Raphael is the only turtle not to have that "love at first sight" when he met Mona Lisa.
- Like her 80's counterpart she is also a scientist on chemistry.
- As revealed by Armaggon that Mona Lisa and Raphael have been sending each other love letters.
- Mona Lisa and Raphael managed to get to know each other more for six months.
- As revealed by both Sean Astin himself (voice actor of Raphael) and Zelda Williams (voice actress of Mona Lisa) that they love and approved Raphael & Mona Lisa's relationship.
- In the episode " Insecta Trifeca" Raphael is seen kissing "Mona Lisa" but pulls himself away from the giant mutant ant. It can be seen that Raphael's tongue being pulled out and trying to use his hands to clean it. It shows that he was French kissing "Mona Lisa" .
- Mona Lisa is the ONLY female character to win Raphael with everything she's got.
- Both Raphael and Mona Lisa are viewed as the "Power couple" in the series.
- Mona Lisa and Raphael have been showing that they might be in physical relationship like when Raphael would puts his hand on Mona Lisa's breast, which of course she doesn't mind and both have been hinting of moving to the next level of their relationship in the future.
- In one of the screen shots story board for "When Worlds Collide" for the ending of the episode. All of the characters outlining are colored in the matching of the characters theme color: Leo with blue; Mikey with orange; Karai with black; April with Yellow, Raphael with red; and Mona Lisa with pink.
- It is unknown why Mona Lisa has pink instead of teal which it matches with her space outfit.
- It could be a reference to her 87's counterpart's pink scarf.
- It's possible that pink is Mona Lisa's true color:
- As pink symbols,sweet, nice, playful, cute, romantic, charming, feminine, and tenderness.
- Pink is also the sweet side of the color red. While the color red stirs up passion, aggression, and action, large amounts of the color pink can actually create physical weakness.
- Mona Lisa's personality is similar to EVE from Wall-E and Sergeant Calhoun from Wreck-It Ralph.
- Mona Lisa has a father/daughter relationship with Commander G'Ythrokka which is a reminiscent to Goliath and Angela whom are a father and daughter from Disney's Gargoyles and Commander G'Ythrokka and Goliath are voiced by the same voice actor.
- Mona Lisa's relationship with Raphael shares many similarities with Rose Quartz and Greg Universe:
- Both Mona Lisa and Rose are from space.
- Both Raphael and Greg are from Earth.
- Both Mona Lisa and Rose are taller.
- Both Raphael and Greg are shorter.
- Both Mona Lisa and Rose are/had fought in a battle.
- Mona's first appearance and her view on Raphael is similar to San the main character from Hayao Miyazaki's Princess Mononoke.
- There are various elements in the episode of "The Evil of Dregg" that resemble scenes from Tim Burton's The Nightmare Before Christmas:
- The ending scene when Raphael and Mona Lisa are seen both staring at each other holding both hands and lean to kiss as a star shines brightly, resembles Jack and Sally's ending scene".
- The part where we see Raphael and Mona Lisa about to kiss also resembles Jack and Sally's kiss, where we do see them kiss but from a far.
- Mona Lisa and Raphael's relationship might be a reference to Lumiere and Fifi/Plummette's since their relationship is flirtatious as well.
- Their relationship is also a reference to Usagi and Mamoru from "Sailor Moon".