Two weeks ago we learned that there was a time when Hodor actually spoke. He was a young man named Wylis.
But now he seems a tad bit … simple? And all he ever says is “Hodor” … why?
Well apparently, Hodor is actually a horse! Really!
Just read on as Redditor Gbinasia drops the science:
And if the (possibly) only girl treating him nicely was Lyanna, it would make complete sense that this is the horse he would warg into. White is a symbol of purity, innocence, and Wyllis/Hodor is all that. He could warg into that horse so that he gets pet, brushed and generally receive attention no girls would give him. Since Rhaegar and Lyanna would eventually run away from everyone, it also makes sense that they would both be on horses while doing so and Wyllis/Hodor would have been witness to many events of that storyline.
So why would Hodor lose his speaking abilities? My guess is that the horse was slain during battle while Hodor was warging into it, which would explain why he is a very much a simpleton now and is afraid of fighting and lightning.
It also sort of explains his penis. Yep.