Merchant of doom/gloom phrase
A person who is pessimistic and therefore forecasts that something bad or unpleasant will happen.
John is a merchant of doom. He is always predicting that the country will be hit hard by the recession.
A: These reforms will only deepen the recession. B: Come on, bro. Don't be a merchant of doom.
The merchants of doom thought that a flood would cover the Earth’s surface.
The origin of this phrase is not clear.
If you swallow the bait, you take something that someone offers you, or agree to do something that someone asks you to do without knowing that it is a trick or way of getting something from you.
You can't just do whatever he wants you to do. Don't swallow the bait.