The Python Demon is a villainess from an episode of the TV adaptation of the Chinese mythological epic ‘Journey to the West’. She is an evil demon who drinks human blood to maintain her youth and power. She has the ability to shapeshift and take multiple forms, but mostly appears as a beautiful princess. She lives in an underground cave in a forest, where she is attended by her servant girls.
Taking the form of a black cloud, the Demon has been kidnapping humans from a nearby village and imprisoning them in her lair to slowly drain them for their blood. The Monk Tripitaka and his three disciples - Wukong, Pigsy, and Sandy - arrive in the area and promise to help to protect the village. The black cloud appears above the village, but Wukong leaps into the sky and drives it away with his magic staff.
Weakened after the encounter, the Demon hurries back to the safety of her lair, where she is comforted by her servants. With her strength depleted, she begins to age rapidly and desperately needs to drink a bowl of blood to restore herself.
Disguised as a peasant, she goes to the village to investigate. She recognizes Tripitaka and realizes eating his flesh would grant her immortality. She becomes determined to capture him. She approaches Tripitaka and wins his trust by pretending to be a starving refugee from a nearby village. She knocks out the Monk and is about to grab him, but at the last moment Sandy intervenes and drives her off again. Wukong and Pigsy set out into the forest to hunt the attacker down.
Retreating back to her lair again, the Demon is despondent. She rues her failure to capture the Monk, as eating his flesh would increase her powers and mean she no longer needs to drink blood to sustain herself. As she is about to settle down to drink another bowl of blood, the Demon is interrupted by Wukong and Pigsy, who have discovered her lair.
Wukong calls her out but receives no response. He blows a cloud of magic dust into the cave, which stuns the Demon and causes her to faint. She collapses onto her bed and transforms into her spirit animal form of a giant python. The snake rushes out of the cave into the forest, pursued by Wukong and Pigsy.
The Demon manages to sneak up on Wukong and devours him whole, but unfortunately for her the Monkey God is alive and well within her belly. He twists and stretches out the snake’s body from the inside, causing her to cry out in agony. Finally, he bursts out of the snake's belly, killing her instantly. Wukong and Pigsy collect the dead snake as a trophy and return to the village to celebrate.