Brewer's Dictionary of Phrase and Fable/Abaris
Ab′aris. The dart of Abaris. Abaris, the Scythian, was a priest of Apollo; and the god gave him a golden arrow on which to ride through the air. This dart rendered him invisible; it also cured diseases, and gave oracles. Abaris gave it to Pythagoras.
"The dart of Abaris carried the philosopher wheresoever he desired it."—Willmott.