What people who either can't write or are too lazy do whenever a paper is due. Any usage of someone else's writing as one's own is plagiarism, no matter how cleverly disguised (or not) it is.
Perhaps the most common way is to search for or download existing papers, cut and paste, change the wording superficially and scramble it a little, and turn it in as your own. Other common methods are to simply copy other students' work in one's class, changing it superficially, or to download or even buy papers online.
Any way you do it, it's a reprehensible practice that can, and should get you in
big trouble. There are known cases where students have been held back a year, or even expelled.
Unfortunately, plagiarism still seems to be a growing problem, and students usually
get away with it.
(note: this entry written by a student)
Student: Why am I getting an A- for this paper?
Teacher: Because it matches three other students' as well as
wikipedia.
Student: No way!
I didn't do it!
Student: And you didn't
prohibit it in the syllabus!
Teacher: sighs I ought to make you rewrite it, but-
Student: I'll sue you!
plagiarism