anesthesia
"I had outpatient surgery last week and received propofol to induce general anesthesia.  By the time the anesthetist removed the syringe from the IV tubing after injecting it, I already felt it taking effect and lost consciousness within a few seconds. Within the blink of an eye, I awoke in the recovery room with no ill effects.  After reading some of the comments here, I worried that the propofol injection would be painful, but there was absolutely no pain - did not feel a thing."