I am king of the sea(but I'm not aqua man) 3.5

[Jayngfet]

Looking at the Rules for animate object it doesn't say that the target has to be a solid object, and:

"An animated object can be of any nonmagical material. You may animate one Small or smaller object or an equivalent number of larger objects per caster level. A Medium object counts as two Small or smaller objects, a Large object as four, a Huge object as eight, a Gargantuan object as sixteen, and a Colossal object as thirty-two. You can change the designated target or targets as a move action, as if directing an active spell."

Size catagories cap off at Colossal so

...can you animate the ocean, or the atmosphere?

The moon?

Could you animate two tetonic plates and threaten the world with earthquakes?

[Flickerdart]

I'm pretty sure the ocean isn't an object. A Colossal chunk of water might be targetable if you bought the DM pizza that day, but aside from that I don't think it would work.

[ocato]

I'd say that since it caps at Colossal, the biggest thing you could animate would be Colossal. The ocean is indeed much larger than that (although it's highly unlikely any being could rival it in size and be terrestrial, thus 3.5 has no size rulings for such a size.) and could arguably be said to be many objects mixed together (like animating a pile of stuff as one object).

[Tengu_temp]

I'm pretty sure that in order to quality as an object, something needs to be more or less solid. Also, the cap at Colossal sounds reasonable to me.

Of course, to animate a Colossal object you need to have level 32 - way into epic levels, when you can already invent an Animate Ocean or Animate Moon spell on your own.

[Chronos]

There are size categories beyond colossal, but they're just unimaginatively named Colossal+, Colossal++, and so on. For instance, some epic dragons are colossal+. It doesn't come up much before epic levels, though.