2 of 2 edited tags; add info from comments

What happens with Energy Drain on an Eidolon?

So, our party with an Unchained Summoner recently had his Eidolon hit by a Wight. How does this work with regard to the Energy Drain?

Does the Eidolon get a negative level? How does that interact with the various curing and healing rules, especially since an eidolon doesn't heal naturally?