One time a friend and I were sitting in his backyard smokin and after a while, we decide to go inside. When I stood up I had a MASSIVE head rush, I started getting tunnel vision and eveything just blacked out. At that point, I felt like I didn't exist anymore, it was just insane. It felt like it had been hours and then I hear my friend saying "hey, hey, are you ok?" and whatnot and I opend my eyes. It had only been like 10 seconds and I was standing that entire time. Really strange..