The Suigin Suigin no Mi belongs to Bandoni Marcello, Captain of the Ferro Pirates. It turned him into a Mercury Human.
The biggest strength is that it grants the consumer to create, shape and turn into mercury, a heavy, silvery-white, poisonous metallic element, and a good conductor of electricity. Mercury is the only metal that is liquid at standard conditions for temperature and pressure. Being liquid metal, mercury has both high density and great versatility; because of this, it can be shaped into any form the user desires, as well as be used in various destructive attacks and to crush opponents. Furthermore, due to mercury's toxicity, wounds inficted by this magic can prove fatal if the mercury enters the bloodstream