CHALLENGE for all you gardening experts: Name that critter

I decided to plant a small corn garden this year. It seems that some critters have taken exception to my decision. Most of the emerging crop has been chopped off as soon as it emerged. Whatever the critter is, it is not going after the seed nor is it eating the greens, just plucking off the tops and leaving it there for me to ponder. I put up protective netting and was able to nurse some of the plants to grow to a foot or more, then moved the netting to a second planting. As you will see in the picture, the critter took out mature plants, chewing the stalks until the plant was on the ground, again leaving the dead plant for me to ponder.

This garden is within a fenced yard that is routinely patrolled by a dog (when he isn't sacked out on his pillow). I'm baffled as to what critter would vandalize a garden patch with no interest in eating the plant or seeds. I've given up on growing corn this year but plan to try again next year. Any ideas??