Hello, lets talk about a hilarious glitch in combat evolved. It is called the Headless Master Chief Glitch.
How To See It: First go onto halo combat evolved mission "The Pillar Of Autumn". Recommended on legendary or heroic to be able to skip training simulation and cryo tube intro.
Once the cutscene where master chief steps out of the cryo tube finishes quickly turn around and crouch jump into the cryo tube. You will see a headless master chief which is a product from the "revile" cutscene where you can see his whole body but you are his head. You may need to try this multiple times because the cryo tube only stays open for about 3 seconds. Another glitch that may happen is if you stop crouching before you fully get into the cryo tube you will either be pushed out of the world or on top of the cryo tube. I hope you enjoy!