Simile

A figure of speech that makes a comparison between two unlike things and uses the words "like," "as," "than," or "resembles."

Example From Text

His whole body was gathered compactly together in the tremendous effort, the muscles writhing and knotting like live things under the silky fur.

Explanation

The author compares Buck's flexing muscles with "live things" to describe Buck's strength and power. Buck is so strong that you can see his muscles moving underneath his fur.