Before They Were Stars: Halloween Costumes!

See Carrie Underwood as a bunny, Nick Jonas as the Blue's Clues pooch and more stars when they were still trick-or-treating!

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JEFF PROBST

"My most vivid memory is how hot it got inside those masks as you ran from house to house getting as much candy as possible," jokes Survivor host Jeff Probst – who was 3 when he donned the Felix the Cat mask for Halloween in Wichita. The best treat to get? "The full-size candy bar. [The worst was] colored popcorn balls. What kid wants that?"