A tomato hornworm can grow up to 5 inches long and as fat as your index finger. They have V-shaped, yellowish-white markings and a black 'horn' or spur on their posterior segment.

Saneishi pointed to a Wikipedia reference for Agrius cingulata, the sweet potato hornworm that turns into the pink-spotted hawkmoth, which has a wing span of 3§ to 4§ inches with a gray-brown ...