You are anathema to psionic creatures and characters.
Prerequisites
Constitution 15.
Benefit
When a foe strikes you in melee combat, the foe immediately loses its psionic focus, if any.
Also, if you are the target of a power, the manifester of the power must spend an additional number of power points equal to the number of psi-null feats you possess, or the power fails (all the power points spent on the power are still lost). This extra cost does not count toward the maximum power points a manifester can spend on a single power.
Special
You cannot take or use this feat if you have the ability to manifest psionic powers, have a power point reserve, or have psi-like abilities.