Guess what it's called? Out of all the things, the seed is this- Herobrine! When you type in the seed, you'll spawn in a forest next to a mountain biome. Ya, not that exciting, since there is nothing scary there. At least it's not like the other, more dangerous seed that is considered the Herobrine seed. To get that seed, type in EEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEE in the seed enter thing (I did not discover that seed). I'm not sure if the Herobrine seed I discovered is only in the Animal Bikes mod, which I have. If someone could, please test this for me.

2012-07-13 11.32.59

The landscape of the world you get when you type in Herobrine as the seed.