Simile

Definition: a comparison between two unlike ideas or things using the words "like" or "as"

Example: 

"busy as a bee"

Berkley by Laurie Lawlor

Black as midnight,
Bad as the devil
With eyes like pieces of dark chocolate,
He thinks he’s king of the world,
My dog Berkley.
He’s very much like a pig
With his pudgy stomach and all.
Like a leech, he’s always attached
To his next meal.

Even though he’s as bad as the devil,
Berkley is my best fellow.

Significance: Similies create new connections between two objects you would have overlooked. It creates visual imagery.