Here's why:
* Malapropism: A malapropism is the misuse of a word, often for one that sounds similar but has a different meaning.
* The Actual Phrase: The correct phrase should be "I'm going to make you sweat blood," which means to make someone suffer greatly.
* The Misuse: The character, Bill, uses "a-going" instead of "going," which is a common grammatical error. However, it doesn't contribute to the malapropism itself. The main error lies in the word "sweat."
The malapropism adds humor to the story because it highlights Bill's rough, uneducated manner, and it contrasts with his serious intentions.