Child porn. There's an official statement from the folks running lemmy.world explaining it. I really wish I was joking, but there were a couple of suuuuuuuper inappropriate posts, even for shit posting standards. I came across one and reported it. It was a porn gif and at the end, there was a text card saying the person in the gif is a child. Fucking pedos ruining shit for everyone else, they should make like a leaf and hang from a tree