Take acid
I can "Make myself see things" to an extent, and I see cats to and fro along with varying other animal forms. Mostly I see things with my eyes closed before bed, very graphic and detailed, along with odd things you wouldn't expect to see that hold a surreal flavor.
PLus the fact that you KNOW you left your body, there's just no denying. The body you're in feels way different, and you can feel the wind and whatever's around you, I saw so much shit last night it was great.