Triple wielding
From Halopedia, the Halo wiki
Triple Wielding is a glitch interrupting with Halo 2's Dual Wielding system. As the name says, you wield three dual wieldable weapons at the same time.
How to perform a triple wielding
1. Let's say that we want to triple wield three Needlers. First, have a Needler in your secondary weapon slot and a SMG (representing an other dual wieldable weapon) in the first.
2. Dual wield a Needler so that you end up having a needler in the left hand and a SMG in the right.
3. Now, trade the SMG for a Needler.
4. You have successfully triple wielded.
Note
- The third beam of bullets comes out of the performer's forehead.