What CAN happen, in no particular order:
Everything you ever get or send through the Border can be searched or seized for inspection/destruction.
Everytime you want to travel outside Canada you can get searched, or your vehicle searched (how deep they search is up to them, it can include taking your car apart).
Depending on how they feel, you can be turned back at the border and not be allowed to cross; fun, right?
Have fun trying to get a passport.
If they charge you with any criminal code offence because you try to import or smuggle something illegal, you are in shit for years.
That's what CAN happen. You asked.
(If you are a minor and you do this, your PARENTS can suffer those consequences instead of you. Nice gift to them, right? )