Dancing Elite glitch
From Halopedia, the Halo wiki
The Dancing Elite Glitch occurs when an Elite Player model crouchs and melees repetitively while wielding a Gravity Hammer, and appears that the Elite is shaking around the place. This can be done in Campaign as Arbiter Thel 'Vadam, Usze 'Taham or N'tho 'Sraom, Multiplayer, Forge and possibly on Xbox Live Matchmaking, such as Grifball.
Method
Simply aquire a Gravity Hammer as an Elite, press the Left Thumb Stick and B over and over. From the Elite's perspective, the Gravity Hammer shakes around wildly, but from a third-person view, a laggy, shaking Elite is shown. It is very hard to do this glitch while running or walking, as is crouching repetitively.
Explanation
This is unknown why this occurs, maybe the Elite model doesn't have a animation for meleeing with a Gravity Hammer while crouching up or down, or both animations overlap each other, using the same model parts such as the Elite's legs, so it shuffles inbetween the crouching and meleeing animations. This glitch will work with the 7-wood as well, but not with any other weapons.
Silent Hammer
A sub glitch, that instead of meleeing, swinging the hammer (or 7-wood) may make it silent while crouching up and down, it might take a couple of tries. It still as the same properties as a normal swing, but instead no ammo will be lost, and a standerd melee 'whack' sound will be heard if in contact with another player, but it will instantly kill.
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