The thousand arms of Avalokiteśvara
One prominent Buddhist story tells of Avalokiteśvara vowing to never rest until he had freed all sentient beings from samsara. Despite strenuous effort, he realizes that still many unhappy beings were yet to be saved. After struggling to comprehend the needs of so many, his head splits into eleven pieces.
Amitabha Buddha, seeing his plight, gives him eleven heads with which to hear the cries of the suffering. Upon hearing these cries and comprehending them, Avalokiteśvara attempts to reach out to all those who needed aid, but found that his two arms shattered into pieces.
Once more, Amitabha comes to his aid and invests him with a thousand arms with which to aid the suffering multitudes. Many Himalayan versions of the tale include eight arms with which Avalokiteśvara skilfully upholds the dharma, each possessing its own particular implement, while more Chinese-specific ones give varying accounts of this number.