Large Brain (3.5e Feat)
From D&D Wiki
Prerequisite: Intelligence 19, and your race must have innate psionic abilities.
Benefit: This feat lets you absorb muscles from your arms and legs to supplement your brain. To catalyze this, you permanently lose 5 powerpoints from your daily total to keep the growth in check. For 2 points of dexterity or strength, you can increase your intelligence by one point. This, however, increases the size of your head, leading to one point lost of charisma for every 2 intelligence gained. This cannot drain strength or dexterity to lower than 10. This loss cannot be replaced by any means save for wish, which will lose you any intelligence points you have gained in return for your other scores.