Bungie.net Thread Me and my friend were messing around with one of my forge maps. He killed me, but I threw I grenade. Somehow it got stuck to him and killed him. My response to this was, "LOLWUT?"
Yeah, I've heard that even in Halo 2 frag grenades can go "inside" the top chest plate near the throat. Haven't watched the video yet, but does it say that you stick them?