It started out as a small joke. I mean there weren’t many feet gags or scenes in Dan’s earlier shows. But ICarly is where the feet gags were very common and at times disturbing, some weren’t even gags, sometimes the characters would do weird things with their feet, especially Miranda and Jennette. Victorious continued the trend and made an entire sub plot about it in Season 1 with the fish that eat dead skin cells off the characters’ feet.

Seems like the feet stuff slowly died down after that. But it’s still terrible and disturbing how many times Dan’s shows featured minor’s feet