Final answer:
In Greek mythology, Cadmus is known for sowing dragon's teeth at a campsite, which sprouted into warriors called Spartoi, but the question does not specify a known event directly associated with Cadmus and his companions camping.
Step-by-step explanation:
The question about what Cadmus and his companions found when they camped for the night does not detail a specific event directly related to Cadmus in historical or mythological texts. However, if we draw from general knowledge of mythology, Cadmus is a figure from Greek mythology who is renowned for founding the city of Thebes and slaying the dragon that Ares had set to guard a sacred spring, an event which could be associated with his actions while at a campsite. Cadmus then sowed the dragon's teeth, from which sprang a race of fierce warriors called Spartoi.