These 22 stories are told by the Goblin to the King Vikram. King Vikram faces many difficulties in bringing the vetala to the tantric. Each time Vikram tries to capture the vetala, it tells a story that ends with a riddle. If Vikram cannot answer the question correctly, the vampire consents to remain in captivity. If the king answers the question correctly, the vampire would escape and return to his tree. In some variations, the king is required to speak if he knows the answer, else his head will burst.

This work is taken form baital pachisi and One of its oldest recensions is found incorporated in the Kath?-Sarit-S?gara ("Ocean of the Streams of Story"), a work in Sanskrit compiled in the 11th century by Somadeva. (Wikipedia)