Life. I've tried it out for awhile. It's kind of interesting. I've had many ideas about it. Sometimes simultaneously.
Some words that come to mind to describe it: a gift, an ordeal, a job, a test, a journey, an experience, a dream, a nightmare, a joke, a mission, a random blip, an accident, a mirage.
Lately, I think it's just an aesthetic experience or experiment. Especially in the sense of "a heightened sensitivity to beauty."
Only in this case beauty must be defined very, very expansively. Big enough to include the ugly, the deformed, the decaying.
Life can't be put in a box. It's a thing that resists boxes.