Admittedly, I hadn't been paying close attention to my cherry tomato plants for a few days. We already had this big bowl of ripe cherry tomatoes sitting on the kitchen counter that we were eating as quickly as we could. Once the bowl started to get low again, I went outside to harvest more.
Eek, a tomato hornworm, ready to strike! No wait, that's a tobacco hornworm (the Wikipedia article through the link explains the difference...otherwise, I wouldn't know either).
In all, there were four Very Hungry Caterpillars, munching away on the Sungold tomato plant. But two of the caterpillars were under attack themselves.
Here's what happened: an adult female braconid wasp encountered this caterpillar. She's tiny (she cannot sting humans) and she injected her eggs under the caterpillar's skin. The eggs hatched into larvae and began to feed on the caterpillar's guts. Having their fill, the larvae emerged through the caterpillar's skin and pupated, spinning themselves into cocoons the size of grain of rice.
If you weren't completely grossed out by my description, watch for yourself:
I dispatched the two caterpillars that weren't visibly parasitized. The two caterpillars bearing cocoons were left alone, as those caterpillars will perish once the next generation of braconid wasps emerge.