I took Apache, my ever-growing bci, outside a few days ago. Just out on the front lawn, but we are far away from the road and neighbors, so it's safe.. When I set him onto the ground, he began sidewinding just like the sidewinders you see on TV. It was really funny looking! I picked him up, and he immediately calmed down.
Maybe the grass just felt alien and weird to him? I thought for a second that he had turned into a rattler...