Drim

Noko is the child in the Ocean's Dream Arc special. He was first seen in the PlayStation game One Piece: Ocean's Dream.

Devil Fruit/Hypnotism
In the game, Noko was shown to have eaten the Nemu Nemu no Mi, a Paramecia-class Devil Fruit. This was not clearly shown nor stated in the anime. This fruit's power is to put his enemies into sleep. In order to activate this power, Noko must use his seahorse flute Tatsu.

Combining his Nemu Nemu no Mi's hypnotic effects with his seahorse flute's mysterious power to manipulate memories makes the fruit's power much more powerful. He was able to take his victim's memories and turn them against the owners.

Anime Differences
In the anime it is the sea horse who steals dreams/memories; in the attempt to make itself a dragon (Sennenryu, Thousand Year Dragon). The child is merely a tool it uses and when the Straw Hats defeat it, releasing all the stolen dreams/memories, the boy runs back to the village.

In the game, Noko's name was changed to "Dream".