Even if you don't know what it is, avoid it

Pastor at my church yesterday read from Isaiah 30 as part of his sermon. Verse 6 reads 

An oracle on the beasts of the Negeb.

Through a land of trouble and anguish,    from where come the lioness and the lion,    the adder and the flying fiery serpent,they carry their riches on the backs of donkeys,    and their treasures on the humps of camels,    to a people that cannot profit them.

 I asked him after the service what the flying fiery serpent was. He said, "I don't know, but I sure don't want to meet it."