Contagious Flame: say at the moment of casting I fire two rays to a target and one to another; in the next round will the first target spring two rays or just one?
Hmm... RAW states that 'a new ray of fire launches from each creature that took damage from the spell in the previous round'...
Which would mean that an enemy struck twice (or more times) will spawn only one ray.
Furthermore, any ray that missed seems to break the chain, as will any creature struck but not taking damage due to Energy Resistance or whatever...