Large Yellow Underwing Caterpillar

Plump, yellow caterpillar with brown dashes on its abdominal segments. It had a tan head capsule. It was 4-5cm long. This caterpillar was alive, but inactive...It was also much more squishy and unresponsive than most caterpillars, so I was thinking that it may have been affected by the cold temperatures, and possibly dying. In this shot, you can see that the caterpillar is defecating and has frass coming out of its rear.