Mandy

Mandy is a character who appeared in Camp Fear. When first met by Grandpa Max, Gwen and Ben, she and her twin Andy would speak by finishing each other's sentences or both speaking at the same time.

They are twins who were very close to each other in the beginning, but came under the bad influence of Ben and Gwen. They were the only people left at the camp, other than Gilbert.

Ben 10

 * Camp Fear (first appearance)