Major Crate a Massive bolder of lead. Size: 1,536,000lb which is ~7ft radius IIRC
Cast Shrink Item. This reduces size by 1/16th in each of the three dimensions, and reduces weight proportionally. The spell references it is about 1/400th, it is 1/4096.
New weight, 375lb
Shadow-Miracle Permanence Shrink Item on the Shrinking Lead Mountain. (For re-use, not necessary for one-shot)
Send lead ball at enemy. Shrink Item specifies that it is auto-undone by "impact", thus at moment of impact, it regrows back to full weight.
Dealing TK damage, based on it's full weight.
1,536,000lb, at 1d6 per 50lb, is 30,720d6.
This is based on the CL cap of 15 for TK.
With a CL of 90+, you could have a Shrinking Lead Mountain that deals 4x as much, or have 4 of the Shrinking Lead Mountains.
OR for
EPIC! WIN!: Ahem. The best weight to damage in the game (That I know of) is the dart at 1d4 for 1/2 a pound. So a 16 pound dart (Colossal +) would deal 4d6. A 65,536 pound dart (size, Colossal 13+) would deal 256d6 damage. After Greater Mighty Wallop for +24 Size, would be counted as Colossal 27+, dealing 32,768d6 damage. Shrink Item on the Dart of Badasseries, reducing its weight to... 16lb
.
So you can throw one dart per CL.
Any that hit expand to deal full damage, but you're well within your TK weight limit.
Permanence lets you re-shrink them with a command word.