The FunGals is an unfortunate employment of what rhetorical device of malapropism.
Explanation:
The word fungals means it is an unfortunate employment opportunities of what is the rhetorical device. In this case malapropism is the rhetorical device is used in this situation.
The malapropism is use of an incorrect word in a place of a similar sounding word which results in a humorous expression. Malapropism is also called as substitute of an incorrect words.