Fevers that quickly cool

• They're all the rage
• Pet Rocks and Beanie Babies, etc., once
• In things
• Widespread rages
• Short-lived crazes
• Crazes
• Fads, essentially
• Furbys and yo-yos, once
• Pokémon and the Beatles, once

Wiktionary Word definitions in Wiktionary
n. (plural of mania English)