I was born in the 1980s. The best one of the bunch from my childhood was the Cinnamon Toast Crunch lightning bites. The girl's curly hair at 8:35 is tamed at first. One bite, and the scrunchie flies off. She then has huge electrified monster wild curly hair thanks to the lightning. I loved that effect.
I think they used stop motion trickery on the girl's hair in the Cinnamon Toast Crunch Lightning Bites commercial. Frame by frame after the scrunchie flies out of the hair, the curly hair gets bigger and wilder. It was impossible to tame that wild mane of hers. They added the lightning for special effects too. Even the boy's hair too.
One of my Favorite Cinnamon Toast Crunch Commercials is Lance The Lifeguard. I used to see that commercial on Television in the Summer of 2000, 2001, 2002 and 2003.