Filthy PCs: The X-rated circus of horrors
Grotesque dust creatures and mummified frogs
Mercifully, some PC invaders are purely terrestrial in origin, although that doesn't make them any less destructive. Ben Wilshaw whipped open a monitor case to find this...
...which on closer inspection turned out to be roasted ants:
There are no ants inside Jim McNelis's machine, because the cockroaches ate them: