Board Thread:General Discussion/@comment-30178351-20160405091519/@comment-28032065-20160418123857

First of all i highly doubt gaster is a skeleton or the skelebros father.

I think Gaster is the skelebros friend and father figure and seeing sans's potential he decide to make him his apprentice and ask to help him build the CORE and reaserching about the player,who soon will come to their world(remind me of Dipper and Ford from gravity falls).gaster scatter through time and space and become some sort of "ghost",who can be only be seen and heard by sans and you.

And the bros'es house probably gaster's and he might be mad because sans use his room and being lazy to even clean it up.