I'm going to steal a teacher's phone and put it in another students locker.
Why do you want to be such a jerk stealing people's stuff like that?
I want to ruin this guy's life.
It's extremely wrong to try get back at another student by framing him for stealing a teacher's phone. Not only will your teacher be upset but that student will experience serious academic repercussions if the school thinks he actually stole the phone. Instead of framing the student, try to work out whatever issues have come up between you and the student in a legal and constructive way.
He's been a jerk to me for a long time. him getting in trouble is a long time coming.
Stealing and framing people for a vendetta is wrong. You should go to you teachers and air your grievances you have with this student to find a resolution.