Evilutionary biologists such as myself thoroughly appreciate the diversity of life and love organisms of all kinds, but parasites are our favorites. David Sloan Wilson is enamoured of the brain worm (i.e. the Lancet liver fluke, Dicrocoelium dendriticum). Toxoplasma gondii is the official mascot over at the Loom. Richard Dawkins seems to take untoward delight in describing the Ichneumonidae (see also here). My favorite are the parasitic fungi, Cordyceps spp. Here's an entertaining blog post about Cordyceps and ants (plus special bonus, the hairworm Spinochordodes tellinii). What's not for an evilutionary biologist to love?