SonSon is a character from the popular crossover, Marvel vs Capcom 2.
She is a humanoid monkey girl who is the grand daughter of a character named SonSon, who starred in an old Capcom game with the same name, SonSon.
In Marvel vs. Capcom 2: New Age of Heroes, she tries to find out why her village was struck by an unknown illness.
Sonson and her father are both based on Sun Wukong, the main character of the Chinese novel Journey to the West. Several of her attacks are derived from the series, such as the size-changing bo staff, Wukong's ability to replicate himself using the hairs of his body, or Sonson trying to cook her opponent in the Shinka Hakke Jin and turn them into sake.