Find a rotting branch in a damp forest. Look closely. Something tiny and bright is staring back. The green elfcup is a cup fungus. It is small and saucer-shaped. It is no bigger than a fingernail. But the colour stops you cold. It is a bright, almost electric blue-green. It looks like someone dropped a piece of jewellery on a log and walked away. The visual is arresting. The scale is diminutive. The colour comes from a pigment called xylindein. It is stable. It is lightfast. The same compound stains the wood green. Woodworkers sometimes use this as a natural dye. A fungus that doubles as a tint. That is efficient. The utility is accidental. The effect is permanent. The stain remains long after the fungus has gone. The cups grow in clusters. They often appear on well-rotted wood where the bark has peeled away. The surface stays damp. They are soft and fleshy when fresh. They shrink to hard, dark crusts when dry. Add water and they revive. Not dead. Just waiting. The resilience is notable. The hydration is key. The structure is flexible. It eats dead wood. That is its job. The mycelium threads through the rotting timber. It breaks down lignin and cellulose. It turns logs into soil. A small fungus with a small role. But the colour is not small. The impact is disproportionate. The function is essential. The decay continues. Do not eat it. Not because it is poisonous. The toxicity is not well studied. But because a fungus that looks like a gem should stay where it is. Admire it. Photograph it. Leave it on the log. The value is aesthetic. The risk is unknown. The restraint is advised. The green elfcup appears in late autumn and winter. This is when the forest is damp. The light is low. That is when the colour works best. A flash of blue-green in the grey bush. A tiny cup on a wet log. It holds nothing but rain. The setting is moody. The subject is vivid. The contrast is sharp. The pigment is unique. The wood is stained. The cup is small. The cluster is dense. The revival is possible. The decay is steady. The forest breathes. The fungus persists. It does not seek attention. It seeks substrate. It finds it in the rot. It colours it green. It leaves a mark. And that seems to be enough.