Mutagen N-7 is the mutagenic substance made by King Nark that he used in a plan to conquer Z-14. This plan horribly backfired turning Nark into a brainwashed mutant and destroying his version of Irk,and possibly filling his universe with deadly energy left over from the nukes.
The Mutagen seems to mutate living things into blonde human females on contact. It can also emit strange telekineic waves that can cause anyone nearby to become a brainwashed slave of King Nark.
Due to the combination of the energy used in the decoy nukes Nark used,the nuclear weapon detonated in his castle created a strange energy that now covers Nark's version of Irk. This energy is known as Fion-Radiation,once someone comes in contact with it they will either mutate horribly or become brainwashed and worship King Nark.