Dancing Grunts

Dancing Grunts are found on the level The Pillar of Autumn, if you manage to sneak and spot the Grunts undetected. Many gamers have claimed that dancing Grunts can be found on other levels, such as The Silent Cartographer. This trick is also the PC version on Legendary. Info can be seen on the video below. Dancing Grunts can also be found in Halo 2 on the level The Arbiter. The Grunts are found after you get into the Heretic Banshee. Dive straight down to large barrels hanging down and in of the crannies are Grunts dancing around a skull. The won't shoot you at all and just ignore you.

http://www.youtube.com/watch?v=UpJraAZsRio