Have you heard of this saying?

Question

Have you every heard of the saying "Shoot a monkey's uncle"? And if so, what does it mean?

Answer 1

I have only heard the term "I'll be a monkeys unlce" Perhaps this is what you mean. Here is the definition for that. If there is a saying "shoot a monkeys uncle, it could be a comeback for the saying below.

Monkey's uncle

Meaning: To express disbelief or skepticism at an idea, or surprise when you find something unexpected to be true.
Example: If Paul Martin remains in office, I'll be a monkey's uncle.
Origin: The publication of Darwin's theory of evolution in the "Decent of Man" was greeted with derision and a great deal of skepticism. The idea that man is related by a common ancestor to apes and monkeys was considered the most outrageous of the claims.

"I'll be a monkey's uncle" was originally a sarcastic remark by a non-believer of Darwin's theory and was intended to ridicule the theory of evolution.