I'm thinking of hiding things that my boss needs then finding them for him so I look like the hero
Does your boss ask for these particular things often?
No, but I can find them in that case it will help me to look like the hero.
People wanting to be heroes is normal but it is not good to achieve that by deceiving people into think that you are one. If your boss finds out, it could get you fired.
My boss respects me. I don't think he will ever fire me and besides, I know what to do.
He respects you because he doesn't know what you're planning on doing, if he got to know what you're trying to do he definitely will lose all the respect for you. It will affect negatively your relation with him and could get you fired. Don't be so overconfident.