fad hopper
A fad hopper is a person who chases every new trend like it's the last donut at the bakery, and they don't care if they leave a trail of broken trends in their wake.
I just joined a TikTok dance challenge and left my old one in the dust.
He had a beard last week and now he’s a full-blown goth.
She had a pet iguana and now she’s into knitting.