The overall description of the 100th episode of Arrow shares a striking similarity to an episode of Batman: The Animated Series titled, “Perchance to Dream.”
Oddly enough, there’s actually already precedent for a storyline such as this in the DC mythos—it’s just not a Green Arrow storyline.
Eventually he confirms his suspicions, and he kills himself in order to awaken to his normal life so he can bring down The Hatter.
In that episode of the iconic cartoon, Bruce Wayne awakens one day to find his parents alive and his alter ego as Batman nonexistent.