Parasitic wasp larvae and caterpillar host. Amazing.

A clip from a National Geographic program In the Womb: Extreme Animals, apparently due to air next week. There's a brief "yuk" portion, but you need to get past that to see the very end, where the effect of the parasites on the host's BRAIN is explained. The "wow" factor isn't the larvae in the body, but rather the behavior of the caterpillar after larval emergence that is truly incredible. Watch and see.

Somewhat reminiscent of other parasites that hijack the brains of their victims (real ones, not sci-fi). Need to blog those some other time...

Via Reddit.