A Jelly-Fish by Marianne Moore

Visible, invisible,
A fluctuating charm,
An amber-colored amethyst
Inhabits it; your arm
Approaches, and
It opens and
It closes;
You have meant
To catch it,
And it shrivels;
You abandon
Your intent—
It opens, and it
Closes and you
Reach for it—
The blue
Surrounding it
Grows cloudy, and
It floats away
From you.

source: "https://poets.org/anthology/poems-your-poetry-project-public-domain"