Devalpa is a type of djinn from Iranian mythology that was said to appear as an old man and wait by the side of a road in order to trick passersby into letting it onto their shoulders by faking fatigue and demanding a ride.
The most famous instance of such Devalpa ensnarement comes from the tale of Sinbad the Sailor.
Once shipwrecked, Sinbad became aware he was not the only castaway having landed in this spot.
The Devalpa, in its guise as a kindly and exhausted old man, asked for a ride across a brook.
However, once upon Sinbad's shoulders, the Devalpa's legs became snake-like and constricting, threatening to cut off Sinbad's air supply.
He was given the choice to work for the creature as its mount or choke to death.
However Sinbad managed to trick the monster by getting it drunk, weakening its grip sufficiently that he could tear free and dashed the monster's brains out with a rock.