Related Clues:

• The Hula Hoop, once
• Wacky WallWalker, for one
• Pokémon, for one
• Kiddie litter?
• Pet Rock, famously
• Passing thing
• Passing fancy
• The Macarena, e.g.
• Attic collection, perhaps
• Passing rage
• Kids' stuff
• It's in for a while
• Extreme enthusiasm
• Major fad
• Playthings