The Teal Buffalo Demon — Cheng'en Wu

Xuanzang was hungry as the group was passing a big mountain, so the monkey went to beg for a meal for him. Before he left, the monkey drew a circle around Xuanzang, Pigsy, and Sandy, and told them not to leave it. They waited a long time. When Xuanzang's patience ran out, they left the circle and were promptly captured by the Teal Buffalo Demon. The monkey came to rescue them but ended up losing his iron rod in a fierce fight with the powerful demon. He turned to many immortals for help, but all failed to subdue the demon until the Taoist Master finally did.