Grenade animation glitch
From Halopedia, the Halo wiki
The Odd Flood Glitch can be found on any level with Infection Forms and Grenades in Halo PC and Halo: Combat Evolved. This strange glitch is possible to perform. Basically, when the Flood Infection Forms are draining your health bars i.e. when your shield is down, right before you die, throw a grenade. The camera will behave just like you died, but your body models completes the animation (and the throw) of the grenade being thrown.
