This theory takes some points in my last theory, I recommend you read it first to prevent any confusing thoughts: My Last Theory.

In case you already read it, let's get started! Most of you may know this, there are some sandstones that are chiseled, with either a Creeper or a Wither . Why are these two creatures chiseled on the sandstones ? You can already guess it, due to its destruction (over 9000 XD). Creepers can blow up your houses or kill you, just like Withers. But is there anything missing here? Yes, the Ender Dragon; to compare, the Ender Dragon is more destructive and can break huge piles of blocks at a time... So why didn't the dragon chiseled on the sandstones? Or should I ask, "Who's scared of the Creeper and the Wither but not of the Ender Dragon?

There can only be one answer to this question: the Villagers. In my last theory, I stated that Villagers are the first people that went to the Nether and when they came, maybe they discovered the Wither, it screwed them up badly so they had to abandon the Nether. Then they chiseled that creature up to remind how strong it is to those that want to fight it. The Creeper is easy, they always blow up their houses (even more powerful when charged), no questions why they chiseled that :D. To conclude, they chiseled the creatures which they're frightened of. However, Villagers also went to the End, why don't they fear of the dragon?

This is where my previous theory take a vital place. Once, the Villagers could go to the End City without defeating the Ender Dragon (Whole story is in my last theory). And when the Endermen decided to create the Ender Dragon, it attacks any players that arrive, but it won't attack the Villagers because they're friendly and helped the Endermen built the cities. Because of that, there are no reasons why Villagers have to afraid, that's why they don't chisel the dragon up.

Are the old players the one who chiseled the sandstones? No, because the Ender Dragon do attack them. So there must have been a dragon chiseled sandstone unless the Villagers are the one who chiseled them

Furthermore, I think the Villagers being the ones who chiseled the sandstones leads to another theory: Did they build the pyramids? Personally, I think they did, with some help of one creature. I will make a specific theory about that later.

That's it guys, hope you enjoy this theory! Debunk it if you want :D