Larvae of syrphid flies in the genus Microdon are so odd that they were originally described as molluscs. The adults are more or less normal-looking flies, but larvae are predators of ant brood, living within the dark galleries of ant nests (in this case, with Linepithema oblongum). Termas de Reyes, Jujuy, Argentina

An Ophiocordyceps fungus grows from a Camponotus carpenter ant it has killed. Armenia, Belize