Answer
Cousin Vicki, played by Dana Barron, was a pivotal character in National Lampoon's Vacation. She was the free-spirited and rebellious cousin of Rusty Griswold, who joined the family on their ill-fated road trip to Walley World. Vicki's outspoken nature and unconventional behavior often clashed with the more conservative Griswold family, but she ultimately became a valuable ally to Rusty and helped him navigate the challenges of adolescence.