Here’s a really cool image from LiveScience:
What look like tennis balls gone evil are actually the tiny suckers on the tentacles of squid. The miniscule suction cups, with diameters of around 400 µm (400 millionths of a meter, or 0.04 centimeters), can be seen in detail in this false-color microscope image. The suckers are lined with fangs (in white) that help grab onto the squid's prey.
