2014-09-20 : If Rite of the Serpent resolves but the creature isn’t destroyed (perhaps because it has indestructible or it regenerated), you’ll get a Snake token if the creature has a +1/+1 counter on it.

2014-09-20 : If the creature is an illegal target as Rite of the Serpent tries to resolve, Rite of the Serpent won’t resolve and none of its effects will occur. You won’t get a Snake token.

2014-09-20 : Rite of the Serpent won’t create more than one Snake token, even if the target creature had more than one +1/+1 counter on it.

2014-09-20 : You get the Snake token no matter who controlled the target creature.