In Buddhist lore, mosquitoes are the jerks of the spiritual world. Lafcadio Hearn’s Kwaidan talks about how Buddhists believe that the pervasive bloodsucker is the spiritual reincarnation of the wicked of the Earth.
A Vietnamese folk tale also tells of the origins of the mosquito. According to the tale, a young man desired to resurrect his dead wife, a vain women to whom he had been devoted. After making a deal with a genie to bring her back from the dead, the young man used three drops of his blood to revive her.
When his wife repaid his devotion by running off with a wealthy sea captain, he realized her vanity and set her free—all he asked was that she return his three drops of blood, since he wanted no part of himself inside her.
Just wanting her husband to leave her alone, she took a knife and pricked the tip of her finger. As soon as the blood began to flow, however, she shriveled to a husk and died again.
She returned as the first mosquito in order to obtain three drops of blood from her former husband to return to human form.