Evanescent
Definition: fleeting; likely to vanish
Why I Looked It Up
I remember the 90s emo band Evanescence (that’s a word too, referring to the property of vanishing).
Also, in The Real Work I found this:
We live in an achievement-driven society in which kids of all kinds and classes […] are perpetually being pushed toward the next evanescent achievement instead of the next enduring accomplishment.