Scanning electron microscopy of the carnivorous fungus Arthrobotrys anchonia capturing a nematode.
Fungi can capture nematodes in a variety of ways but the most sophisticated and perhaps the most dramatic is called the constricting ring. An erect branch from a hypha curves round and fuses with itself to form a three-celled ring about 20-30 microns in diameter (30/1000th mm). When a nematode "swims" into a ring it triggers a response in the fungus and the three cells expand rapidly inwards with such power that they constrict the body of the nematode victim and hold it securely with no chance to escape. It takes only 1/10 th of a second for the ring cells to inflate to their maximum size.
Link | Many more amazing pictures of fungi at George Barron's website.