I intend to use an NPC to make her attack a vessel. The NPC is capable of using Metamorphosis as a multiclass Ardent 7, manifester level 11. My idea was to make her metamorph into a flying creature, fly directly above the vessel and then turn into a huge rock, crushing the deck and part the hull.

The vessel in question is a Dromond, I use "Stormwrack", for sinking the vessel 15 hull sections (each a 10 feet cubes) would have to be crushed, each with hardness 5 and 80 hp. The Dromond has a 20 feet by 100 feet space. The whole ship has AC -3, attacking a hull section is AC 2.

My problem is to assess the power of my imagined kind of attack. Metamorphosis says:

> You can also use this power to assume the form of an inanimate object.
> You gain the object’s hardness and retain your own hit points. You can
> take the shape of almost any simple object you can think of, such as a
> chair, a sword, or a rug. (...) You cannot use this power to assume the
> form of a psionic item or a magic item, or any object with a hardness
> of 15 or higher. (...)As an inanimate object, you lose all mobility.
> You retain your normal senses and your abi lity to speak. You
> can manifest a power if you make a Concentration check (DC 20 + power
> level); however, doing so ends the duration of this power. If you take
> damage while in the form of an object,your actual body also takes
> damage (but the object’s hardness, if any, protects you). *Expanded Psionics Handbook, p. 117*

Stone does have hardness 8, so turning into a rock is possible. The NPC would take falling damage minus 8 points of hardness. But how much damage would the ship take? The NPC could turn into a 11 HD creature - but there seems to be no limit regarding objects.

An inch of stone in a 5x5 feet square has 15 hp. (PHB, p.166) The character has 117 hp. The manifester retains her hp. So maybe you could say she could turn into a stone slab of 5 feet by 5 feet 7 inches thick. This slab would have 105 hp. You could transform it into a stone ball of roughly 3 feet diameter. This is a massive boulder - but just how massive in terms of damage?

A granite ball of 3 feet diameter would weigh roughly 1,16 tons. This is more than 11 times 200 lb, so the DMG section for falling objects applies: This boulder causes 11d6 points of damage on a 10 foot fall, for a 100 feet fall 20 d6 damage would be applied to the ship and 9d6 of damage to the NPC (minus 8 pts of hardness).

While this seems reasonable, I am still wondering: Are any or these specific limits inherent to the power or could you just use Metamorphosis to say "I turn into a mountain" and bury the ship? Or simply put: How big a rock can this character turn into using Metamorphosis?