Spirogyra. Spirogyra is a green algae belonging to the class chlorophyceae. it's very rampant in damp areas such as pond and wet walls, even in decaying plants, here is a spirogyra on the wall of my fence, I went close enough to take this and I discovered it had tiny filements they're highly alive and dangerous when viewed with a microscopic machine
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From @josediccus