The sarrukh possesses the supernatural ability manipulate form. The ability is one of the game's most powerful and versatile and it's essential for the overpowered kobold Pun-pun. However, the special ability says, "At will, a sarrukh can modify the form of any Scaled One native to Toril, except for aquatic and undead creatures" (Serpent Kingdoms 80–1 and emphasis mine).
Other than using the character rebuilding rules from Player's Handbook II, is there a way for a creature that's not native to Toril originally to become native to Toril later?
Official 3.5 material, nonupdated Third Edition material, and Dragon magazine material is fine, but third party material is not. Also, this question is about what works and not what's balanced. (I mean, it's a question about Pun-Pun, so I hope that was already clear!)