Mafumafu (まふまふ) is a producer who's mostly known in the Nico Nico community of as an utaite. Since 2012 he has also started to produce original Vocaloid songs. He mainly uses IA, though he also uses Len, Miku, Rin, and GUMI. He often pitches the Vocaloids high in many of his Vocaloid works.
He is also known as Kagami Mite Shisshin-P (鏡見て失神P, lit. Looked in the Mirror and Swooned-P). However, it should be more considered a joke rather than his -P name.