I will consume your soul
Since when did people make crazy threats over something like borrowing a pen? Okay, we know that when you are the only one in class that brings pens and constantly gets asked if you can borrow them out, it gets annoying. Most of the time you never get it back or they use all the ink in your pen.
Then you feel stupid for being the person who spent a lot of money on school supplies when everyone else just coasted off you. So actually, the more we think about it, this person is right, touch their pens and you risk losing your soul. It seems like the punishment matches the crime.