>> it goes from like confusion to like, questioning, to just getting on board and being really elated about it. >> 9-year-old sebastian thomas is the youngest person ever to participate in an improv everywhere mission. ♪ i think santa's stupid ♪ i'm almost 10 years old now ♪ last year i asked for robots, santa gave me an army guy ♪ >> fourth graders singing about santa, it's pretty funny. ♪ you're never too old to sit on santa ♪ >> onlookers aren't sure who to trust. take this woman, for instance. >> she went up and said, what is this? they were commiserating on why