Hopefully, you are asking what can happen to someone who commits plagiarism out of curiosity, and not because you have found yourself in a compromising situation.
The consequences for plagiarism are going to vary slightly depending upon your school. If you attend a private institution that makes its own rules, there is a chance that you could be kicked out. However, you need to find that out for yourself, as every school is going to be different.
Whether or not you attend a school with such a strict policy, you are going to have to face some consequences. You might receive a zero or a failing mark on the paper. Chances are the teacher is not going to just tell you that you can write it over and try again. Many teachers are bound to report cases of plagiarism and they could be in serious trouble if they do not report you.
You could receive a detention or suspension. Furthermore, your teacher is probably going to become rather suspiscious of you, and be carefully looking at your future work to make sure that this problem does not occur again. Your reputation as a student will be tarnished.
The consequences for plagiarism are similiar for college and high school. However, remember that many colleges are private, so you are going to be dealing with the rules of the institution. If you get kicked out of college for plagiarism, you might have a very difficult time finding another school that will accept you into their program.
You are usually writing even more serious papers in college than you were in high school such as a thesis or final paper which you need in order to graduate. If you plagiarize on that assignment, you are not going to graduate!
Once you leave college, you cannot begin plagiarizing either. First of all, it is wrong to steal someone else's work. Second of all, some colleges will revoke your diploma if they find out that you plagiarized.
Plagiarism continues to be a problem in the work force, particularly in the fields of the arts. You do not want to run into issues with this problem in the work place. You could very well lose your job if you are found guilty of plagiarism. Additionally, if you are presenting someone else's work as your own, that person could technically sue you.
On a larger scale, if your company is found out to have problems with plagiarism, the company is going to lose its reputation. This statement particularly holds true if a college professor or board member is found guilty of plagiarism. People are going to be wondering what kind of instructor has been teaching their children, and what that instructor has been teaching them about morals and ethics in the workplace.
If you have committed plagiarism, there are no advantages to continuing to cover up the plagiarism. You should consider confessing to the plagiarism in order to avoid or mitigate the negative consequences.