Howard Pendergast is a delusional scientist who manipulates Gayle Marsh into becoming the super-villainess Psi to help him destroy civilization under the pretense of eradicating "decay".

When Pendergast attempts to kill Psi for her failure to defeat Supergirl, she transforms him into a decaying monster before eventually restoring him to normal.

Decay is a living statue created by Phobos to earn the approval of his father Ares.

[3][4] Julian Lazarus later resurrects Decay by transferring its spirit into a virtual replica before Wonder Woman destroys it.

Decay battles Superboy and Doctor Psycho before the latter subdues Sarah and traps her in a peaceful dream world.