Please do.
Minute Form, Complete Arcane 115. It's the opposite of Giant Size, Complete Arcane 110. Both Wu Jen 8 spells.
Also, take to mind you must start with a level in Commoner to be able to have Commoner flaws, so you'd have to start with Terrasque 1//Commoner 1. And considering the entry requirements (Climb 5 ranks!), the next level you couldn't be a Tasted just yet either.