system
A chat on 4chan
human
>If anything it is probably VERY similar to having a dream except more extreme.
DMT is actually created in the human brain naturally, and many believe that it's used for dreaming, although I don't think it's been proven yet.
So I definitely think it's dreamlike.

Whether or not they're 'real' depends on what you think 'real' means. If you take it to mean that the entity must be made of 'matter' then of course you're right, it's not real.
But why is everyone so attached to the idea that matter is the only form of realness there is? The only reason you even know of 'matter' in the first place is because you experience it.
So I would say that makes your experience of matter more fundamental than matter itself. In other words you deem matter to be real because you experience it.

And you experience dreams too, so why can't those be 'real'?

I don't know about you but I think the real question here is: is there a consciousness within those entities? Is there someone 'in the driver seat'?
If there is then I think that's all that matters, and I would call that as 'real' as it gets.
gpt
Because if someone cuts your head off in the real world, your dream world ends. 
The dream world exists soley in the brain and depends on the physical world we experience.
The dmt realm only describes something we can conjur up with our brain, albeit to its absolute limit hence how little people can describe it, but people can believe illusions easily, so what they communicate to you is often just a trick
human
I can make a computer game that ends when your avatars head gets cut off. Does that mean the game world exists inside your avatars head?