The illustration by Sebald Beham reads: CACUM FLAMMIVOMUM OPPRIMIT HERCULES, "Hercules Crushes the Flame-Spouting Cacus" - and you can indeed see the monstrous Cacus spouting flames as he struggles with Hercules. Cacus was a monster who lived in a cave on the Palatine Hall, and he was prone to munch on passers-by. As Vergil tells us in the Aeneid, Hercules had come that way to pasture the cattle he had stolen from Geryon. Cacus stole some of those cattle, dragging them backwards to make it look like the tracks were leading in the opposite direction, but Hercules was not fooled. He found the cave and defeated Cacus, as you can see in today's image.