Common Clubtail Gomphus vulgatissimus

Named for its obvious distinctive feature, this medium-sized European dragonfly sports a unique club-shaped abdomen that makes it instantly recognizable. Here's the weird part: males start life black with bright yellow markings, but those yellow stripes gradually turn green as they age. This means a freshly-emerged male looks completely different from an older one. They spend their brief adult lives hunting near slow-moving streams and clean rivers with sandy bottoms—specialists of their habitat.