Population of nematodes under attack by Myzocytium
Nematodes are attacked by hundreds of species of fungi. Myzocytium has zoospores that track the nematode by its body secretions then fasten onto the cuticle by lectin/carbohydrate bonding. The cuticle is penetrated by a narrow peg and the contents of the zoospore pass into an infection 'thallus' inside the host. The thallus grows longer and longer and longer as it absorbs the nutrients from the living host. Eventually the filamentous infection thallus makes up more than half the body volume of the host and the nematode succumbs. The thallus becomes septate into short cells and each cell enlarges and rounds off to form spherical to ellipsoid thallus segments that, at maturity, look like a chain of beads inside the body of the host.
Each segment eventually functions as a zoosporangium, produces an exit tube to the exterior and the body contents cleave around the nuclei to form spores that develop two flagella. The mature zoospores then swim out through the exit tube to attack another nematode. Or something like that!