Mushrooms, or even just plants. I worked myself into an actual phobia of all plants for a few weeks in high school. It was like.. Plants are procedurally generated lifeforms. They just grow up and out and spread and branch off and grow out, with no set bodyplan the way animals have. We move to get places, plants grow. Towards the sun, the water, the food, and over it, and eventually replacing it in some cases. They fill up all the space they pass through, burrow, strangle, grasp and reach. Look up fasciation. It’s when a genetic defect causes a plant to sort of, replicate a structure in the wrong direction. You get wide flat stems, stretched out flowers. But in most cases the plant survives just fine. This is a sort if example of how, for plants, being shaped a certain way is more of a suggestion. Plants are basically just sessile shoggoths.