As in Hinduism, the Buddhist nāga generally has the form of a great cobra, usually with a single head but sometimes with many. At least some of the nāgas are capable of using magic powers to transform themselves into a human semblance. The nāga is sometimes portrayed as a human being with a snake or dragon extending over his head. One nāga, in human form, attempted to become a monk; and when telling it that such ordination was impossible, the Buddha told it how to ensure that it would be reborn a human, and so able to become a monk.