... or, if you wanna get technical, a One Piece (is that even grammatically correct?) Devil Fruit idea. Feel free to contribute opinions, whether they be positive or negative (or both)! Seriously, I like what I came up with, but feel like it's a... bit much.
Virus-Virus Fruit: The user gains the ability to inflict viruses (like how a virus infects a computer, not sickness-related) of various types on people, depending on what part of the body is touched (for the most part).
The types of viruses that could be inflicted include Poison (does not kill, only severely weakens; temporary), Paralysis (temporary, has to touch an arm or a leg in order for it to work), Freeze (very slow; temporary), and Mind Control (has to touch chest or face; works as long as controller is within a close distance providing verbal orders; Haki users are immune).
Dipping the inflicted body part in water immediately ceases the effect. All types, with the exception of Mind Control, are temporary.
The user is also able to touch the ground and "infect" the ground, creating a trap. They active when someone steps on them. The types for this include: Flames, Shock, Vines, and Pitfall. Unlike the touching, Haki users aren't really immune.
The fruit takes over the user's body and mind, corrupting them. It could take up to thirty years to take full effect, but it basically turns the user into an emotionless shell of a human being, like a robot.
Thoughts? I feel like I may have went a bit far with this, but the user is a forty-eight year-old female pirate who's been sailing the seas for 20+ years, and has had the Devil Fruit for around the same amount of time.