Idea mode activate I think that in a later update herobrine should be added and you can toggle him on/off in options and Notch could make "2X2 tunnels" a generated structure (if herobrined was toggled on )
Herobrine could be hostile, and attack you if you look at him, like an enderman. and there can be only one herobrine in the world at a time please take this into consideration Notch.
