Hold an eel by the tail idiom
To try to grab someone or something that is elusive.
He is a slippery salesman, so it is difficult to hold an eel by the tail.
The plan seems hard to hold an eel by the tail to keep up with the progress of project.
Stock market is hard to hold an eel by the tail in the COVID-19 pandemic.
Deceitful, calculating, and unreliable; elusive.
The verb "hold" should be conjugated according to its tense.
Used to allude that the last force, problem or burden which is seemingly minor and small causes a person, system or organisation to collapse or fail
Her husband's violent act last night was the straw that broke the donkey's back and she left him