Word for temporary obsession
How about a flare?
a sudden burst, as of zeal or of anger
http://dictionary.reference.com/
A passing fancy:
- A passing fashion, activity, or feeling lasts for only a short period of time and is not worth taking very seriously.
(Cambridge Dict.)
- a word for "temporary obsession" is "infatuation".
Vocabulary.com puts it as:
Infatuation is falling in love with or becoming extremely interested in someone or something for a short time.
Maybe it just your latest craze
Latest craze n.
1: an exaggerated and often transient enthusiasm : mania 'the latest craze in music'
Reference: 'Latest craze' n. Merriam-Webster Dictionary online. Accessed 03/03/2015