Penicillium chrysogenum, the source of penicillin (? is it not penicillium notatum). Image from Discover Magazine. It never fails to amaze me that much of what we call design or art is simply a reflection of the natural world.
Very devious - The common cold virus, constantly mutates to avoid detection. Just how totally viruses can overcome a healthy host is seen when an infected human cell ruptures, releasing a stream of new viruses (blue) into the system.