This lot first appeared back in the 1983 story Enlightenment and would make for perfect monsters in new Who givien the current love for formless beings. The Elementals were elemental beings of immense power but limited creativity. They existed on another plane but needed to feed off of the emotional energy of lesser beings, which they refer to as ephemerals in order to be anything but incredibly bored. In their story they abduct ships from throughout history and fit them with ion drives and sails for solar winds, then abduct humans to race them in an interstellar race. The race was set up by the Guardians of Time with the promise of something called Enlightenment as the prize, although the Fifth Doctor put an end to that by throwing a captain who nearly won the race overboard. Some of the Eternals even passed themselves off as Gallifreyan deities such as Time, Pain and Death. The new series could literally use them in any kind of scenario they like, possibly one involving Eternals posing as Gallifreyan gods once again or another where they kidnap humans from Earth to once again take part in some sort of competition. The possibilities are endless, and given theyre almost impossible to dispatch it would make for interesting viewing and give the Doctor a real challenge.