Pun-Pun
Pun-Pun is the god of munchkinry. The ultimate example of "breaking the system" in 3.5, Pun-Pun is an ECL 6 kobold character build that can cast every spell and psionic power at will, has infinite stats (and therefore infinite HP), and has a divine rank of 30. While the original version of Pun-Pun was a 12th level psion, the most recent shattering of the system uses only standard divine/arcane magic and setting-specific splatbook feats.
The build relies on a particular interpretation of the Manipulate Form ability, which allows the user to raise a stat on another character to the same level as the user's corresponding stat. Pun-Pun can only attain apotheosis if this refers to the user's modified stat: the infinite-stats exploit only works if Pun-Pun can (1) give himself a stat bonus, (2) raise his familiar's stat to the same level (permanently), (3) command his familiar to use Manipulate Form on Pun-Pun, raising Pun-Pun's stat permanently, 40 goto 10. If the DM rules that Manipulate Form can only raise someone's stat to the user's unmodified corresponding stat, with no bonuses, then the sploit doesn't exist. Then again, if you try to build Pun-Pun in an actual game, your DM may actually pee in your Mountain Dew.
Pun-Pun will bitch slap you for 1dAssload damage. Do not fuck with Pun-Pun.