Well i guess since jackasses have been bumping up old threads lately i figured this couldnt hurt.

I can live for millions of years, but I am constantly changing.
When you try to grasp me, I slip through your fingers.
If you did grasp me, I would be no more.
What am I?
Couldnt that also be a dream, dreams can last for a long time, such as like flying maybe, but things change it ya know, like new technology. When you try to grasp it, it can metaphorically slip through your fingers, cause you didnt achieve it, but then when you do grasp it, its not a dream anymore, but a reality..?