Oh, the zombie ants. Yeah, that is crazy scary.
A few days ago I went on a Wikipedia article-hopping spree, where I eventually ended up on the page for "Amniotes". Amniotes are animals that have a protective layer around their offspring during gestation (in humans, the "amniotic sac"). While that in itself is not that exciting, the article pointed out that this protective layer was an adaptation of formerly aquatic animals to be able to have offspring on land. Fish are all anamniotes because they don't need that layer, but all land-living animals are. Except amphibians, who circumvented the problem by reproducing in water, and then leave it when growing up.