E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
A sort of fairy in human form, whose abode is the caverns of rivers. Sometimes these dracs will float like golden cups along a stream to entice women and children bathing, and when they attempt to catch the prize drag them under water. (South of France mythology.)
Fare le drac, same as Faire le diable. Irish, Play the Puck; English, Play the deuce.