Imagine an alien world where there are are shallow lakes where electricity generating beings (like electric eels or whatever) would power many of the land dwelling creatures, including the dominant inteligent species (before they invent machines that would do that). They would go inside a lake and "charge themselves" like a smartphone or other things that we use on Earth.
Because of this those aliens would be more gentle (they wouldn't need that much food) and would probably enter their version of "Industrial revolution" much sooner than other species (since they used electricity since the begining).
I initially had an idea that giant exotic trees could have microorganisms inside them that generated electricity (they could have giant holes like Sequoia trees) and aliens would go inside and "charge".
Ideally,those beings wouldnt need to eat at all,and recieved all energy they need from electricity and drinking water (or some other solvent). Feel free to sugest something that sounds more realistic/better for you.