Mero Mero no Mi

The Mero Mero no Mi is a Paramecia type Devil Fruit that allows a person to fire a beam that uses a person's emotions, particularly emotions of lust or perversion, against them, particularly in transforming them into stone. "Meromero" is an onomotopeia of "to fall down drunk", including being overcome with emotion such as love or lust. It belonged to the Tenryuubito who fed it to Boa Hancock.

Strengths and Weaknesses
This Devil Fruit's basic power is to allow the user to turn people into stone. This occurs when Hancock's hands form a heart shape, and beams are shot out of the shape. Anyone with "dirty thoughts" will be turned into stone. As Hancock proved, she was also able to reverse the petrification process if she so chooses, but it is unknown if she could do this if the victim is petrified within a certain period of time, or she can do it to anyone who ever became petrified because of her ability. As demonstrated by Vice-Admiral Momonga, the effects can be countered when the intended victim focuses their mind on other aspects such as pain, blocking out the "dirty" thoughts. Luffy did panic from her Mero Mero Merrow though, believeing it to be a Noro Noro Beam and was afraid he'd end up slowed down again, his fear apparently countered any feelings of lust for her, although this is proven false when he realised it wasn't the same move, she attempted it again. According to her sister, Boa Sandersonia, it was because he was afraid he was going to die. Luffy also avoids even the simplest of Hancock's powers (being able to make people fall in love with her no matter what she does) simply because of the fact she "pisses [him] off" with her vanity and lack of regard for the lives of her people. Other than that, this fruit doesn't seem to have any specific weaknesses outside the standard Devil Fruit weaknesses.

Usage
Basically, Hancock used this Devil Fruit power to petrify her victims. However, the contradictory story her fellow Kuja give 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. However, the story turned out to be a lie. Hancock's Devil Fruit was fed to her originally for entertainment purposes only and so while unseen being used this way, it means the Mero Mero no Mi has a degree of performance value.

Hancock has also been able to use a "Pistol Kiss" by blowing a kiss, creating a heart-shaped bullet to fire at her victim by aiming it with her index finger. The projectile probably hits its target with the sharp end of the heart, so when it hit Luffy, it penetrated his rubber skin. Its relationship with the Mero Mero no Mi is unknown.

QUEM QUER PÃO?''' Hancock forms a heart shape with her hands and launch a beam of the shape. Anyone with "dirty thoughts" (lust) that is hit by this beam will be turned into stones. The beam's effect can be blocked if the target focuses doesn't have any lust for Hancock, either by focusing on other emotions (as Momonga) or simply being ignorant (as Luffy). Mero Mero Merrow reminds Luffy of Foxy's Noro Noro Beam.

EU QUERO PÃO''' Hancock blows a kiss to create a heart-shaped bullet and fires it.

Trivia
The Mero Mero no Mi's ability to turn people to stone was based off of the mythic Gorgon's ability to turn its victims to stone upon looking directly at them.