Writing Exercise 080

It's time for writing exercise number 080 already. Time sure flies by! :o
This week my task is to write a riddle. Let's see if you can find out what I'm writing about. I'm sure you will. :D

2017/06/23 – riddle

I see something you don't see,

Hanging from a willow tree,

Spinning on a single thread,

Far away from a spider's net,

It is wiggling,

it is jiggling,

Waiting for the wane of the moon,

Once it turns into a cocoon,

Tell me now, what did I see

Hanging from that willow tree?