Related Clues:

• It's hot until it's not
• The Macarena or Psy's horse dance, e.g
• Crosswords, e.g., in the 1920s
• The "Macarena" dance was one
• Short-lived thing
• Planking, e.g
• Pet rocks, e.g
• Current "in" thing
• Nose rings, e.g
• It's all the rage in Vogue
• Thing in one year and out the other
• Mean-reverting deviation, in economics
• Pog or Pogs, formerly
• Thing with constant level
• Personal whim