Our expressions today all contain the word 'cat'.
'To bell the cat' means to do something dangerous. Something that might end in disaster. The expression comes from an old story.
A family of mice could not leave its hole to get food, because of its fear of a cat. The mice decided to tie a bell around the cat's neck. The bell would ring as the cat moved. So, the mice would always know where the cat was. All agreed it was a wonderful plan. That is, until one wise old mouse asked; "Who will bell the cat?"