You receive a devil fruit. It can be any known or unknown devil fruit ranging from completely useless to incredibly powerful. All devil fruits share the same weaknesses, though some devil fruits possess their own unique weaknesses. Someone who has eaten devil fruit cannot swim due to the fact that when they are submerged in water they are sapped of their physical strength and energy. This does not cause their abilities to become deactivated. This is mostly still water. You can still take a shower and you are not drained by just becoming wet you must be submerged and Haki can reverse or nullify the effects of a devil fruit.