Smell a Rat: This is very useful when we are describing something that goes wrong but don’t know why.
Go to the Dogs: This is very useful when we are describing someone or something is going down and need to snap out of it.
Fishy: It is very useful to describe something is strange happening.
Take the Bull by the Horns: We can use it when someone decides to do something to correct something else.
Let the cat out of the Bag: Let someone else knows what is going on before the things actually happen.