This activity is a great way to teach extended metaphor.
The teacher assigns a "key word" for the student groups to use in their comparison to humans. Some of the best key words have been:
Humans are like:
Using the worksheet, students work in small groups to brainstorm ways to extend their simile. After about 20 minutes, each group takes a turn presenting their ideas without sharing the key word (robots, computers, etc.). The rest of the class should try to guess what the key word is based on the quality of the comparisons.