"He just started punching me in the face," said Jameel Grant, the victim.
His eye is still swollen and bruised and it's been nearly a week.
Joshua Jones, 26, was arrested on Saturday.
Jones is charged with reckless endangerment, assault, endangering the welfare of a child and menacing.
Police say Jones pummeled the boy after jumping on a school bus carrying the 11-year-old and other special needs kids.
Jones allegedly got on the bus through the unlocked back emergency exit at a corner near P186 in the Bronx and then jumped off the same way.