To "bell the cat" is to cripple or disable a
powerful adversary using a method dangerous or reckless to the
one performing the task.
The term comes from the Aesop's fable "the little mice plan to bell the cat", which is about a group of mice plotting how to deal with a cat that has been decimating their ranks. One mouse comes up with the idea of placing a bell on the cat so that the mice could hear it coming, and therefore remove the cat as a danger.
Each mouse congratulated one another on the brilliance of their idea
until one mouse asked, "who will bell the cat?"