The Bible tells us that they arrived in the land of the Gerasenes, and behold, they met a man who was demon-possessed. The Word tells us that this demon-possessed man wore no clothes, he did not dwell in his house, but his house was the tombs:
And when He stepped out on the land, there met Him a certain man from the city who had demons for a long time. And he wore no clothes, nor did he live in a house but in the tombs.
This devilish man was very aggressive with everything that crossed his path, and this is because he was demon-possessed, he was possessed by legions of demons.