Mary and I sat outside and chatted while the kids used chalk to draw on the fence, poked at various critters with sticks, and discovered the strangest caterpillar I have ever seen. Behold, the Gulf Fritillary caterpillar.
It seems we discovered our spiky, orange friend during the nymph phase of his life- though he gives "nymph" a less-than-graceful name. Fortunately, the black spikes are soft to the touch, though the creature himself is poisonous if ingested. Being poisonous keeps the predatory insects at bay. Milla might have gotten around to some form of ingestion if we hadn't urged the sparing of his unfinished life.
Apparently, this fellow feeds only on specific species of passion flower, which explains he is also known as the passion flower caterpillar. Now it remains to be seen where passion flower can be found in our yard.
The life cycle, nipped from Wikipedia, shows the extraordinary metamorphosis. You can see the birth of the butterfly from the chrysalis in this photo.