This requires a 10th level psion, of at least Medium size, with the power metamorphosis.
The 5th level psion power metamorphosis is similar to polymorph self, except that it allows the *manifester* to assume the form of objects, as well as creatures. Assuming a Medium-sized caster, the largest object that can be assumed is Large-size. According to the PHB glossary, a Large (creature) is 8-16 foot in size. Assuming that the same goes for objects, we'll try for a 16' cube of gold, for 4096 cubic feet. That gives a weight of 4,915,200 lbs, for a damage of 24,576d6 when dropped from a height of 10 feet. You can fit 9 Medium-sized creatures underneath that block, for a grand total of 221,184d6 damage, or a mean of 774,144, or 86,016 per person.
You can shapechange into any object less than 200' in any dimension. For this, we'll assume the form of a 200' cube of solid gold. Gold weighs about 1,200 pounds per cubic foot, so a 200' cube of gold weighs about 9,600,000,000 pounds.
For every 200 pounds an object weighs, it deals 1d6 damage for falling 10 feet. (DMG, page 89.) Our cube of gold, therefore, does 48,000,000d6 damage. On average, that's 168,000,000 damage. Now, you can fit 1,600 Medium-size creatures in a 200' square. Add up all the damage you deal to all of them, and you get 268,800,000,000 damage
Archer said:That whole series has already been debunked over at wizards.
Archer said:Permanent stat increases are limited to a +5 inherent bonus...
Archer said:...and recommended minimum DC for epic spells are 10.
Archer said:Permanent spells have a x5 DC multiplier applied before any negative modifiers.
Archer said:Fortify spells with instantaneous duration are useless because the benefit expires instantaneously.
Archer said:Instantaneous spells have no ongoing effect. Fireball doesn't keep on burning, heal doesn't keep on healing and fortify doesn't continue its fortify effect. Wall of Stone etc create a non magical object and have no further effect.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.