I was at my grandma's house and found a door that was never there before, it blended in perfectly with the wood walls and opened when I got closer to it. I stepped through and it shut behind me, and when I looked back it had disappeared. I was in a huge warehouse with a concrete floor and really bright flourescent lights up above. There were lots of aisles kind of like a supermarket, but with long glass aquariums instead of shelves.
Even in the dream I was kinda creeped out, so I didn't look at a lot of the fish inside the tanks. I remember seeing multiple tanks that looked a bit like ant farms? And in them were "clams"... Imagine an accordion, but the middle part is pale, veiny flesh sandwiched by 2 clam shells and that's what they looked like. Some of the clams had holes in their flesh and were pulsating a little.
Another fish I saw was this giant red eyeless eel that seemed to be coming out from the side of the glass wall. It kept eating and throwing up the same hermit crab over and over. I decided to stop looking at the fish at that point.
Past the aisles was this small open pit about the size of a fridge, and inside it was stuffed with fluffy white circles that I registered as bunnies. There was a guy talking to a big crowd behind the pit. I don't know what he was saying, but he reached inside the pit and pulled out a canvas bag full of something red that was leaking through it. He then turned to me and asked if I'd like to pet the bunnies and I said yes of course.
So he let me down in but a bunch of other people were jumping into the pit too and I was really upset because nobody was letting me in. I don't remember much after that, except at the end I finally got back to my grandma's house and when I told her everything that happened she shrugged and told me that's just how life is sometimes.