Well, I googled "DMT entities shiny plastic" to see if I could find people describing what I saw, and holy fuck. First try and everyone here definitely appears to be describing what I saw on my first few trips.
Essentially, as I took the vapor in, I was looking at this plastic yellow stoplight lamp that the friend who ordered it for me had sitting in front of me. As the room started to sort of disassemble, the lamp stayed in my field of vision, morphing and flying in and out of it. Next thing I remember was a flash of images I mostly couldn't comprehend, but I remember seeing something that looked like those naked gas masked things in the "Goodbye Blue Sky" segment of Pink Floyd's The Wall film sort of haphazardly crawl-sprinting from my upper left periphery to the bottom right, then appear as a morphing image which seemed to be a mix of a cartoony open mouthed, wide eyed face shaking it's head and hands of some sort using some kind of sign language or gesture. The next thing I can recall is feeling as if I was sliding or pivoting through a series of colorful plastic rooms, horizontally, vertically, forward and backward until this being appeared in front of me. It sort of looked like it was made of the textures of the lamp, but it had reassembled into a round plasticy head of sorts, with perfectly round(red, I believe) eyes, and a sort of lever like "neck" which went into the "floor", which it used to pivot an implied(not seen or felt, as I had no body) "platform" under me, and took me into more rooms. It's movements were incredibly fast, but smooth and precise. It either rotated itself or me so that it was behind me, and I heard/felt these gargled electronic, syntactical noises shoot through my head, from left to right. It was as if there was a robotic alien conversation physically going through my head. I couldn't understand it, but right after doing this, it felt like it grabbed a hold of my brain and started working my inner thoughts like some sort of puppet. Making me think to myself in english, "This is what you asked for. This is what you wanted." Needless to say, I was pretty terrified(more like being constantly startled), as this was my first time in hyperspace. I REEAALLY wanted off the ride by that point. I don't remember if this next thing happened before or after that, but at some point it started waving a finger like appendage in my face a couple times for a split second. I came down shortly afterwards, and that was the most I had seen of them. However, my next three DMT trips showed me glimpses of them. I think I was still in the tunnel because it came as part of a flash of transforming images, but it came after I saw the face shaking/sign language image again, only it wasn't attached to floor. In fact it floated over to me, but I was taken to another place where there were these red(if I remember right), shiny, autonomous marbles that rolled around through this complex system of slides. They rolled up and down the inclines, seemingly unaffected by any sort of gravity. And wan MOE thang: I hit the residue of my pipe while on the peak of a light mushroom experience, and I saw objects in my room become shiny plastic "robots" of sorts. They didn't move but I felt then as if they were alive. Maybe unrelated, but the aesthetics were eerily similar. Plus, I got a glimpse of the "lego" entity's face, while I was being quite literally murdered on a 110mg 4-ACO-DMT trip, but I'll probably share that and more, as I learn how to use this site, on my own post or something.
Anyway; Sorry for the long post. I wanted to quote some of you who mentioned some of the things I saw, but I just made this account right after reading this page to share it, so I don't really know how to use it yet. Does anyone know if I can upload images from a phone onto this page? Shortly after I had my first trip, I made a half assed drawing of the entity I saw. Maybe some of you might find similarities. I attached it to this post, but when I click it it brings up a white page with "You have insufficient rights to download this resource. Contact forum administrator for further details." in tiny black text at the top.