I believe the correct answer is: a leaf.
In the poem Possum Crossing written by Nikki Giovanni in 1943, the subject advocates the putting of the sign “Possum Crossing” enraged by her neighbors not paying attention to the animals on the street, which results in taking their lives. While driving through the mist, subject sees the light hopping and hits the breaks assuming that it is an animal, but it turns out the be just a leaf:
“I hit brakes for the flutter of the lights hoping it’s not a deer
or a skunk or a groundhog
[…]
I look . . .
relieved and exasperated ...
to discover I have just missed a big wet leaf
struggling . . . to lift itself into the wind
and live.”
