He is a shapeshifting robot.
Funny, kind of smart, loves Pecha Berry Pie.
Has a bag of video game power-ups, can shapeshift into any video game character, can live off of food, water, or batteries, programmed with human feelings and personality.
He was built by his world famous scientist "parents". He was programmed with all human abilities, feelings, and even looked exactically like a human. However, something went awry in his programming, and he gained his power to shapeshift. He attends school like a regular 11-year-old, and hides his identity pretty well.