Hie Hie no Mi

The Hie Hie no Mi is a Logia-type Devil Fruit, eaten by Aokiji.

This fruit allows the user to turn himself, as well as things around him/her, into ice, and control it as well.

The meaing behind it's name: "Hiehie" means "chilly."

Weakness

Though this is yet to be demonstrated in the series, presumably extreme sources of heat and flame can counter this ability, as they melt ice.