User blog comment:FazbearFreak/Doing a FNaS AMA/@comment-26813439-20160622214925/@comment-27812664-20160627192425

As referenced in FNaS 3, Herobrine was always supposed to make an appearance in all the games, but never did.

Other than him, a Slime and Silverfish were supposed to appear in FNaS 2. Also, a Spider was supposed to be in FNaS 3.