Chain Lightning: How many times does it 'leap' to a new target? Does it hit non-hostile enemies? Does it have a priority on who it 'leaps' to?

The destruction spell, Chain Lightning, is described as a:

Lightning bolt that does 40 points of shock damage to Health and half to Magicka, then leaps to a new target:

How many times does Chain Lightning 'leap' to a new target? Will increasing the Destruction skill or getting certain Destruction skill perks increase the number of Chain Lightning's 'leaps'?

Does it hit non-hostile enemies? Does it have a priority of any sort when it 'leaps' (e.g. like hitting enemies first, before non-hostiles) or does it simply choose the nearest reachable NPC or creature?

Chain Lightning is actually an area of effect spell. There are no actual leaps, it just hits everything in a 20 foot radius around its point of impact. I don't believe any perks or skills influence the radius of your AOE spells. The description is just deceptive fluff. As all offensive AOE spells, it does not discriminate between friend and foe.

Source: personal experience, UESP Wiki.