A psionic villain superteam/organization in Champions Online.
PSI was once led by Sebastian Poe, a scientist who worked on a serum that induced and enhanced psychic powers. To be sure, he tested it out on him and his infant son, Kevin (without his wife's knowledge). After a while, he met the accountant, Madeline Bruner, who found out what he was up to. She seduced him, making him inject her with the serum, marry her, and break up with his wife, who took their infant son with her.
As Madeline was married to Poe, she owned half of all Poe's companies. She made him create a group of powerful psionics, who eventually took over the Scarlatti mob organization, as well as a key VIPER nest in Baltimore. They were called PSI. Eventually PSI was taken over by Psimon.