Halo Reach Easter Eggs/Secrets

[Jei_your_basic_zombie_humper]

Heya People, I finished Halo Reach yesterday afternoon. I know I'm slow and only completed in like a day (I got it early on 13th), but hey! It was on legendary!
So after seeing the ending and such, I'm looking to see what things I missed.
So what easter eggs and secrets have YOU found.

I noticed/unlocked the following:

Spoiler

How Noble Six dies through a final survival mission called Lone Wolf. And at the Beginning of the game (2nd Mission, what happened to the 1st?) there is a invisible enemy/something that runs from the distress beacon, it is what scares the wildlife which come running from the next point to check out. Just Sprint and jump towards the beacon as fast as you can and you will see something running from it and towards the where the farmers are hiding.

 

[AwayFromKeyboard]

Ive found that as well, can you kill it?

 

[Shru1kan]

Ive found that as well, can you kill it?

Well, try? I mean tag it with the pistol if at all possible and keep rushing it. gonna try it now, if I get it I will edit this post. If not, assume I fail.

 

[TheTaco007]

You have to kill it on legendary, and you get the first data pad of the game. It's not an easter egg.