Correct: Nip it in the bud means to stop the growth of something.
Incorrect: Nip it in the butt.

Correct: Toe the line means to conform to a rule or standard. It comes from the idea of placing your toe on a line as when starting a race or standing at attention in a line.
Incorrect: Tow the line.

Correct: Wreak havoc means to inflict violent and needless disturbance .
Incorrect: Wreck havoc.

Correct: You have another think coming means you have an opportunity to rethink.
Incorrect: You have another thing coming.
[This one came as a surprise to me.]