Anti A.T. Field

An Anti A.T. Field is the term given to a type of energy that S² Engines are capable of producing which neutralizes existing A.T. Fields. The result is that individual A.T. Fields - the light of the soul, barrier of the heart, the "ego" - collapse, and the soul is freed from the body. In Lilim this results in the individual's body reverting back to its original form which is LCL because a body cannot maintain its shape without an A.T. Field.

Second Impact

The Anti A.T. Field generated by Adam in Second Impact was powerful enough to exterminate all local life, including microorganisms. If Adam had not exploded, it's possible that the Anti A.T. Field being generated by her would have been able to exterminate all life on Earth. Instead, the entire South Pole was "formatted" into an uninhabitable "dead sea".

Third Impact

The Anti A.T. Field generated by Lilith in the form of Rei in The End of Evangelion during Third Impact neutralized all existing A.T. Fields on Earth. This freed individual souls which were then collected within her egg, resulting in Instrumentality.