Oh yeah, that happened to me on Sierra 117 after I sniped some brute.
On a side note: Everytime I activate the IWHBYD skull my armor permutations go away and I can't use any of them unless I deactivate it, anyone else get this glitch???
funniest thing ive seen in halo was from Halo 1. There was two hallways that formed a T. And I was just looking down the hall and running in the other hall going past the opening was an elite screaming. Then two seconds later a bunch of flood went by after him.
I was playing Halo 2 once, and an elite stuck a grunt for no reason! I know he didn't see me, because I had the envy skull on and was using active camo. Plus, I had no marines with me. I just couldn't kill him after that. It was great.
In halo 1, on the first level when you are finally coming out of that Forerunner underground area, there is an elite with a sword who appears in the cutscene that follows you unlocking some doors. I had forgotten about him when I came to the place and screamed in panic as he lunged toward me, hoping not to die. I looked back at the TV to hear me shields fluttering and the Elite dead in front of me, sword on my foot. I was like 'WTF!?!!?!?' I didn't kill him! I turned around the corner to where he was running from and saw the parked warthog I had left, still holding a sniper reloading and a gunner's minigun spinning . I was amazed to find that even on Heroic they were able to kill him, having milliseconds to do so before I was toast.