Mero Mero no Mi

The Mero Mero no Mi is a Paramecia-type Devil Fruit that allows a range of attacks which use emotions of lust or perversion to transform opponents into stone. It was eaten by the ShichibukaiBoa Hancock, who was force-fed it by a World Noble.

Strength and Weaknesses
The major strength of the fruit, as demonstrated by Boa Hancock, is that the user is able to transform those who lust or love after the user into stone in varying degrees by using their "dirty thoughts". Victims that have been completely turned to stone are incapable of consciousness and susceptible to physical damage unless the user de-petrifies them. Petrification can also be achieved through physically striking an opponent, although the only area that is turned to stone is the contacted area, as opposed to the entire body. The power also extends to nonliving objects, including Pacifistas.

The powers of the fruit can cause any victim(s), whether they're male or female, with feelings of lust to fall for the user as any feelings of lust they have will be strengthened and aimed towards the user, making them even more susceptible to the fruit's petrification effects. Since Hancock possesses near unparalleled beauty, enticing men with her powers takes very little effort while with women she will use more flirtatious and "cutesy" behavior. Apparently, once the petrification takes effect, the victim or victims experience a state of suspended animation where their subjective sense of time is completely halted by the fruit's power, effectively making it look to them as though time itself has stopped from the victim's point of perspective, and will last this way unless Hancock chooses to relinquish their petrified states.

While the fruit's powers, specifically the aforementioned technique, use the focused lust of a user's victim to fuel the petrification, if the intended targets have no sense of lust or cannot see her (such as being blind), then the powers are nullified. This can be achieved either by being distracted by other emotions, such as pain, bitterness and fear, or by simply lacking lust to begin with. For example, Vice-Admiral Momonga was able to resist her powers by stabbing his hand, and Monkey D. Luffy initially believed the attack aimed at him to be an attack from Foxy's Noro Noro no Mi, but it is later revealed that Luffy is immune to her powers due to him having a pure heart, thereby having no wicked or ill intentions on his part. There have been others shown to be capable of resisting her beauty, such as Smoker, Crocodile, and Dracule Mihawk; whether this means they feel attraction but have enough willpower to suppress it or they are simply too hardened to be affected by the fruit has yet to be revealed.

Other than that, this fruit does not have any other known weaknesses aside from the standard Devil Fruit weaknesses to water and Seastone.

Uses
Hancock uses this Devil Fruit power to petrify her victims. However, the contradictory story that her fellow Kuja are given is that she and her sisters killed a Gorgon and were "cursed". The Gorgon gave each sister a set of eyes on their backs. Whenever anyone sees the back of her and her sisters, they turn to stone. This story is actually a lie, concocted to hide her shameful past as a slave at the hands of the Celestial Dragons. Hancock's Devil Fruit was originally fed to her for entertainment purposes only.

Even without the use of any kind of special technique, Hancock can use her great physical prowess to attack in hand-to-hand combat; her Devil Fruit gives her the ability to turn anything she strikes to stone, and also does not need the victim to lust after her. This allows her to take down opponents that possess little to no thought (like the Pacifista).

Attacks

 * Mero Mero Mellow (Mero Mero Merō, literally meaning "Falling-Down Drunk Sweet Wind"): Hancock's signature technique, she forms a heart with her hands and fires a heart-shaped beam from them. Anyone with "impure thoughts" (lust) towards Hancock hit by this beam will be turned into a stone statue. Any affected persons' body can be destroyed, due to the fact that it is stone.


 * Mezameyo (Mezameyo, literally meaning "Awaken"): Hancock blows a kiss at a target that was previously turned to stone, which causes small hearts that wash over them and restore them to their normal state. The pun here is that all accounts from former real-life slaves refer to freedom as an "awakening"; so too are the "slaves" of the Mero Mero Mellow essentially "awakened" from the "slavery" of petrification stasis.


 * Pistol Kiss (Pisutoru Kisu): Hancock is able to use a projectile-like move by blowing a kiss, creating a heart-shaped bullet to fire at her victim by aiming it with her index finger, which she uses together with her Busoshoku Haki to hurt the foe. The pun here is that the kanji for gun is part of the phrase "jū no tsutsu", meaning "gun barrel", which Hancock's index finger is essentially serving as, in order for this technique to work. It is unknown if this attack carries the same petrifying properties as the rest of Hancock's attacks, as it has only been used once against Luffy, who has no lust towards Hancock.


 * Slave Arrow (Sureibu Arō): Hancock breathes in deeply and kisses out a heart; similar to her Pistol Kiss, but much bigger. She then pulls the heart back with a hand and, with a pop like that of a bubble, hundreds of arrows (all of them tipped and fletched with a stylized heart design) are fired and barrage her opponent(s) before petrifying them; the sheer number of arrows unleashed makes this move particularly difficult to evade. This technique not only petrifies anyone and anything that it hits, but somehow manages to freeze them in place, regardless of whether or not they were in motion or not, to the extent that she even stopped cannonballs in their tracks. The pun in this technique is that, although the kanji used here may mean "imprisonment", it can also mean "captive", as in someone being captivated by love.


 * Perfume Femur (Pafyūmu Femuru, literally translated as "Aromatic Leg"): Hancock does a handstand and spins around in order to deliver a series of kicks. Anything she strikes, whether animate or inanimate, instantly turns into stone and, in turn, breaks from the sheer force of her kicks. Unlike her other attacks, only the immediate area around the point of contact turns to stone, not the entire object. The pun here is that when Hōkō, the actual pronunciation of the first two kanji symbols, is written another way, it can mean "apprenticeship" in the sense of "indentured servitude".

Trivia

 * Not knowing that it is actually the power of a Devil Fruit, the Kuja of Amazon Lily attribute Hancock's ability to turn people to stone to a curse that she and her sisters supposedly got from defeating a monster called a Gorgon, hence their title, the Gorgon Sisters.
 * The ability of the Mero Mero no Mi to turn people to stone is similar to that of the mythical creature, the Gorgon Medusa, who was able to turn her victims to stone simply by looking directly into her eyes.
 * Aside from "Pistol Kiss", all of Hancock's techniques have a pun referring to captivity of some kind and have many idioms about love capturing someone. This is ironic considering Boa Hancock's own past and her dislike of slavery and captivity.
 * As a gag, Sanji was turned to stone when he first saw Hancock even though she had not used her power on him. This is because Sanji already had impure thoughts when he saw her. He returned to normal moments after. This repeated when he saw Shirahoshi.
 * In SBS Volume 35, Oda mentioned thinking about including the Ero Ero no Mi into the series, then also called the Love-Love Fruit in the English version of the SBS. This concept apparently made it into the series as the Mero Mero no Mi.
 * In One Piece: Pirate Warriors 3, several of the characters are immune to Hancock's Mero Mero no Mi powers, both when encountered as an enemy or when Hancock is being controlled by the player. However, only one of them is canonically confirmed.
 * Tony Tony Chopper is immune to being petrified by Boa Hancock's Mero Mero no Mi powers, which is a reference to his lack of interest or attraction to human females. His immunity is also somewhat ironic given Hancock's dislike for small animals, regardless of how cute it is. Chopper himself will even remark on the Mero Mero no Mi having no effect on him if he defeats Hancock in battle.
 * Luffy is also immune to the Mero Mero no Mi's petrification powers, which is confirmed in the source material.
 * Admiral Fujitora is also immune to Hancock's petrification abilities, which is a reference to his being blind and not knowing what Hancock looks like. This is shared by another non-canon source, in which Sebastian was also immune due to being blind.