NOTE: This build requires a very liberal interpretation of polymorph any object and a DM willing to see how far you can push the system. The fact that you're subconsciously considering this build right now means you probably aren't able to play it. Thowwy! Be an Elan or another LA0 creature of the Aberration type. Take 1 level in any class you want, though I recommend Conjurer for Abrupt Jaunt or Druid because you're durable, you have an animal companion, and it saves you a level later in the build. Plus, you can heal yourself. Rar.
Take 2 flaws. I normally take Murky-Eyed and Noncombatant. This lets you take the
Assume Supernatural Ability feat. Take Assume Supernatural Ability twice; once each for a Beholder's Antimagic Eye and its other eyebeams. You'll probably need
Mercantile Background (
Player's Guide to Faerun) so you get +300G to spend.
Before hitting level 2, amass 1200 gold. Beg, steal, borrow, or create the money. Mercantile Background helps.
Go to a major metropolitan center like Sharn or Waterdeep. Pay 1200 gold and find someone to cast
polymorph any object on you. Turn into a Beholder, or an Elder Orb (
Lords of Madness 41) or something that passes for a True Beholder. Thank the DM.
Become a Beholder Mage (
Lords of Madness 42). You're now an X1/Beholder Mage1. Woohoo! Take a moment, if you wish, to marvel at this accomplishment.
Disintegrate a support pillar in joy if you'd like.
Go X1/Beholder Mage4. Ensure you have at least one metamagic feat. Any metamagic feat will do. You'll also need 4 ranks inKnowledge: Arcana and 8 ranks in Spellcraft.
Become an Ultimate Magus (
Complete MageGreensinger Initiate. Before you enter Planar Shepherd (
Faiths of Eberron 105), you need 4 ranks in Knowledge: Planes, 8 ranks in Knowledge: Nature, and the Wild Shape "class feature."
After you have Druid5 (or
Divine Minion or Wild Shape from another means), enter Planar Shepherd. Ideally, you're a Planar Shepherd of Xoriat which gives you 60 (!) rounds of You Time for every round of Their Time. If you wanted to be slightly gentler, go Dal Quor for a 10:1 turn ratio.
Get at least 5 Planar Shepherd levels for Planar Bubble. Enjoy playing the game as if you're in
Braid World 6.
After that, assuming you can fit it into 20 levels, Initiate of Mystra (cast in an
antimagic field) or Dweomerkeeper4 (Supernatural Spell 1/day).
This may be the most powerful character that doesn't rely on infinite or nearly infinite loops.