Stun

Stun was in Halo:CE and Halo 2, but were two diffrent things in each game.

Stun in Halo Combat Evolved
When a player is shot with a Plasma Weapon, done better with the Plasma Rifle or the mounted gun on a Ghost], it will be harder for them to turn or move. A example of this is how when a [[Ghost strafes around a Scorpion while shooting it the main cannon will not turn fast enough to get a lock on the Ghost. Now if the Ghost were not shooting the scorpion would have easily destroyed it.

Stun in Halo 2
While playing a Campain level you may throw a Grenade at a group of enemies but not kill all of them. Some, mostly Jackals and Grunts, will put their hands over their head and start walking in a random direction slowly.