Doku Doku no Mi

The Doku Doku no Mi, or Doku Doku Fruit, is a Paramecia Devil Fruit that grants the user the ability to produce poison, as well as grant immunity to it, effectively turning him/her into a "Poisonman". It was eaten by Magellan, the Warden/Chief of the World Government prison Impel Down.

"Doku" (毒) means "poison".

Strengths and Weaknesses
This fruit's major strength is that it basically grants Magellan the abilities related to poison. With it, Magellan can release a poisonous gas when he sighs, as well as it grants him immunity from poison, thus allowing him to eat poisonous food without dying (and a flavor that he enjoys).

The weakness of this fruit seems to be that Magellan doesn't have the ability to control his powers too well, as when he sighs, he releases his poisonous breath even amongst his allies. Also, while he can eat poisonous foods without dying, they apparently still upsets his stomach, making him suffer diarrhea. Other than that, the user is affected also by standard Devil Fruit weaknesses.

Trivia

 * When Magellan talks to himself, there is a little pun stated by Hannyabal in response. The Japanese word for soliloquy is "Dokuhaki". "Doku" means "alone". The Doku part however stated by Hannyabal is replaced with a different "Doku" meaning "poison".
 * This Devil Fruit is very similar to the non-canonical Noko Noko no Mi, both of which manipulates poison, as well as releasing them in a semi-uncontrollable way.