How to instantiate on collision?

I am making this psychological horror game and basically i want the game to instantiate a mad doctors face when the player collides with an invisible cube. I know how instantiate works (Instantiate(what, where, rotation)), but how would i instantiate the doctors face and destroy it again after a very short duration when the collision occurs? I know that the script should include the instantiating bit, and destroying both the instantiated doctor and invisible cube. What would the (Unity)script look like?