Invincibility

Invincibility is a new piece of equipment featured in Halo 3.

It confers the user with a brief period of invulnerability. This period lasts about 10 seconds. When activated the player is covered in shining bands. It is known to be possessed by some or all Brute Chieftains in Halo 3, giving chieftains a brief period of time where they may chase after the player with the Gravity Hammer unhindered, giving them a significant tactical advantage. In campaign, it can be found on some dead Brute chieftains that haven't used a powerup yet. Curiously, if you melee a Brute in the back (assassination hit) while the invincibility is active, it will still kill him. In addition to being obtainable from dead Brute Chieftains, there is an Invincibility in the level "Halo". At the top of the Control Room tower, where you have to fight hordes of Flood, there is an Invincibility. After going up the staircase, go to the left and into the tunnel. It will be there. Note: This is only found on difficulties Easy, Normal and Heroic. It cannot be found there on Legendary.

It has a similar appearance to the Cloaking equipment, except that it glows a gold color, rather than a cool blue color. It's symbol on the HUD is Two overlapping, intersecting ovals.

It is not present in multiplayer, unless you edit gameplay options where you can make players invincible. NOTE: The guardians can still kill you.

In campaign, though you will be invulnerable from almost all forms of attack, you may still die from falling or having a large object such as a Scorpion crush you, or by having tons of Infection forms infect you. Immortal characters like the Arbiter who become betrayed by you can also kill you.

Trivia

 * Players can get this equipment if they instantly kill the Cheiftain without getting too close or killing it's allies. Spartan Lasers, Brute Spike Grenades or Plasma Grenades are good ways of getting Invincibility. Quickly sniping the Chieftain a number of times also works, but even on Normal and Easy, it can take a full clip. So just be sure that you're one Hell of a sharpshooter!