Can you polymorph into an animal companion version of an animal using Beast Shape or Wildshape, given that it's the appropriate size?

Specifically, can an Order of the Beast cavalier transform his mount into a roc companion, since it is a medium or large animal?

I have seen another thread largely agree that A. you cannot use templates in polymorph and B. you can only transform into animals that have rules written for them (i.e you cant just be a "Huge wolf" with the right Beast Shape because that doesn't technically exist); moreover, if something doesn't exist in the game world, you could never find a piece of that animal for use in Beast Shape (not an issue for druids and cavaliers, though).

Thoughts? Have there been any official rulings?

I'd say it's ruled out by this line:

Unless otherwise noted, polymorph spells cannot be used to change into specific individuals. Although many of the fine details can be controlled, your appearance is always that of a generic member of that creature's type.

Animal companions are never "a generic member of that creature's type," each one is specific individual with stats and abilities determined by the class that grants it.

But hey, if you're looking to turn your mount into a giant bird you can always go with the impaler shrike. Slower flight speed than the roc and only one attack, but the bite it does have gets a lovely 10-ft. reach and 1.5x Str bonus to damage. Plus that one's definitely legal.

If you can't turn into a 7th level fighter, you can't turn into an animal companion w/the abilities from a 7th level druid. Like Avoron says there are a few other large flying animals tho'.

I'd say it's ruled out by this line:

Polymorph wrote:

Unless otherwise noted, polymorph spells cannot be used to change into specific individuals. Although many of the fine details can be controlled, your appearance is always that of a generic member of that creature's type.

Animal companions are never "a generic member of that creature's type," each one is specific individual with stats and abilities determined by the class that grants it.

But hey, if you're looking to turn your mount into a giant bird you can always go with the impaler shrike. Slower flight speed than the roc and only one attack, but the bite it does have gets a lovely 10-ft. reach and 1.5x Str bonus to damage. Plus that one's definitely legal.

That's an interesting bird. I didn't know that existed. This whole issue arose for me trying to find a substitute for the Giant Falcon from Frog God Games, which I only noticed recently to be 3PP. The main thing I care about is the presence of three attacks; otherwise, it would simply be an almost straight downgrade from the mount's original tiger form. If you know of any other medium/large birds (or dinos, winged mammals, etc that fall under "Animal," please let me know).

On the topic of rules, thanks for that line. It's interesting, and I was unaware. The one response I can see is as follows: under the animal companion heading of the roc bestiary entry, it says that a roc companion is simply a baby roc. In other words, it is a generic specimen, simply at a different time in its life (as opposed to, say, a mindless vermin companion that only becomes agreeable and servile under the case of druidic magic).

Obviously this is subject to DM approval, but do you think this would violate RAW?

Pteranadon is large

Pteranadon is large

Same issue as the shrike: it only has one attack. Its flight is also clumsy, but that's a secondary issue.

On the topic of rules, thanks for that line. It's interesting, and I was unaware. The one response I can see is as follows: under the animal companion heading of the roc bestiary entry, it says that a roc companion is simply a baby roc. In other words, it is a generic specimen, simply at a different time in its life (as opposed to, say, a mindless vermin companion that only becomes agreeable and servile under the case of druidic magic).

Obviously this is subject to DM approval, but do you think this would violate RAW?

Unfortunately, I don't think that will fly... no pun intended. The animal companion is a baby roc, sure, but it's not simply a baby roc, or else it wouldn't grow more powerful in pace with its master's experience. It's a roc that's been enhanced by the special bond it's developed with a humanoid, giving it customized feats, skills, and abilities. I don't think you can polymorph into a specialized creature like that any more than you can polymorph into something with class levels.

If you know of any other medium/large birds (or dinos, winged mammals, etc that fall under "Animal," please let me know).

To my knowledge, the list of medium and large flying animals suitable for polymorphing goes as follows: dimorphodon, dire bat, enchanter heron, giant raven, giant vulture, gliding turtle, impaler shrike, and pteranodon. Unfortunately, every single one of those animals is limited to a single attack, so they might not be very helpful.

Honestly, you might be better off just finding an alternative source of flight for your tiger, so it can keep its lovely pounce and rake abilities. An animal totem tattoo, for instance, might soon be in your price range, and it can give your mount five minutes of flight each day to divide up as needed. And hey, if you go for the bat totem it can also provide some handy blindsense in an emergency. Then you can just use your wild mount shape for out-of-combat utility, and you don't have to worry about losing natural weapons.

many animals can temporarily fly if launched using a trebuchet

and of air walk. The tiger will walk or run on air, so it maintain its ability to pounce.

overland flight at those higher levels... my raptor often soars through the air, and i do not mean raptor as a bird...

Flying require a lot of skill to do it well. Animal companions have few skill points. Air walk don't require any special skill to work.

Flying require a lot of skill to do it well. Animal companions have few skill points. Air walk don't require any special skill to work.

Well, it does require Use Magic Device on your part, unless this is one of those rare spellcasting cavaliers. Add in the ongoing cost, and you'd probably be better off investing in a set of gale armor barding or some greater suspension piercings.