Falling creatures as objects

[Arcane possession]

How should this scenario be ruled. A player flies upto 500ft and summons a crocodile above an enemy head.
My confusion comes does this creature class as an object now only dealing 4d6 x 2 due to being a large creature and more than 150ft above. The rules for falling objects also states the object takes the same damage it deals. Is the damage on top of or instead of the normal falling damage.
Another question that comes to mind is that the enemy receives a dc15 reflex save to half damage if he notices but what is the dc to notice the falling object and does that increase if croc is invisible.

[Arcane possession]

Another question if it takes a full round to fall 500ft. Would the attack take immediate effect if only dropped say 200ft?

[JohnHawkins]

You cannot summon (using Summon monster) a Crocodile in mid air as it cannot fly ,
Next actually hitting a man sized moving target from 500 feet with a dropped object is practically impossible unless you have a self guiding object (winged kamikaze crocodile), you certainly need to take into account the winds, if the crocodile becomes unstable in flight(needs wind tunnel testing, also effects the surface area on the ground subject to Crocodile impact, this will also be variable depending on how much the crocodile panics (will save for the crocodile or a too hit penalty?)), target motion and launch speed.
I recommend a series of practical experiments, you are going to need to decide if alligators, Nile Crocodiles or Saltwater crocodiles make better projectiles and then select the best release mechanism to simulate being summoned. If snout shape varies within a species that will also need consideration as it effects the aerodynamics of the falling crocodile.

Anyway this is all silly you would be much better off summoning a Whale or Elephant for greater mass and surface area

[Bob Bob Bob]

Falling object rules. The short answer is that there's a table for the amount of damage things do (based on size), you halve the damage if it's not something dense and heavy like stone (most creatures aren't very dense or heavy), you halve the damage if it falls less than 30 feet, you double it if it falls more than 150 feet. Both object dropped and thing struck take the same damage. If you're targeting a specific creature it's a ranged touch attack with (usually) a range increment of 20 feet. If they know it's coming they can make a DC 15 reflex save to halve the damage.

So all that said, it's 4d6 x 1/2 x 2 for being a Large Crocodile more than 150 feet up (crocodile are less dense than stone, presumably). It doesn't say that this replaces the falling damage rules so presumably the crocodile also still take falling damage. The DC to notice is probably the perception DC for a visible creature (DC 0) modified by distance, wind, etc. Invisibility would add +20 as normal for a moving creature. As creatures fall 500 feet a round, the perception check is probably when the crocodile is still 500 feet away.

Not that it matters in this case, because "A creature or object brought into being or transported to your location by a conjuration spell cannot appear inside another creature or object, nor can it appear floating in an empty space. It must arrive in an open location on a surface capable of supporting it." So no raining animals down on people. Also the ranged touch would be at -50 or something for being 500 feet away, I'm not sure that would ever hit. It doesn't say what happens on a miss, presumably a small crater and blood stain just appears under the person you missed.

[Claxon]

Creatures cannot be summoned in places that cannot support them. That means only flying creatures can be summoned in the air. A crocodile must be summoned on the ground.

So....they can't do this in the first place.