So, I just discovered Pup Shape (School transmutation (polymorph); Level druid 3, sorcerer/wizard 3, witch 3) and, since my Cohort is a Foo Dog (Magical Beast, Extraplanar), investigated protecting him from the spell - using Spell Immunity.
The short description on the SRD Spell List(s) says, "Transforms a single animal or magical beast into a younger and cuter version of itself...etc." So, I was concerned.
However, the spell description allayed my fears: http://www.d20pfsrd.com/magic/all-spells/p/pup-shape
The Target is listed as "one animal"
The text says, succintly, "You transform the subject animal into a Small magical beast (or a magical beast one size category smaller than the original creature, whichever is smaller)"
So, this spell cannot affect my Foo Dog, since he is not an animal, but is a magical beast.
I was wondering about some past uses of the spell so looked here in the forums and, unequivocally, everyone is saying it can affect Magical Beasts.
Has no one read the spell? Or is the spell as listed on the SRD incorrect? Or am I reading the spell description completely wrong?