Kill the Goose that Lays the Golden Egg

Meaning:
To get rid of something that is profitable to you.

Example:
Tearing down the top attraction in the theme park, “The Haunted House”, would be akin to killing the goose that lays the golden egg.

Did you know?
This idiom originated from Aesop’s Fables, in the tale of a greedy couple killing their goose who laid golden eggs, thinking that they would find more gold inside.

Reference: http://www.englishclub.com/ref/esl/Idioms/K/kill_the_goose_that_lays_the_golden_egg_649.htm