US publisher Atlus had its website hacked last week, and the naughty "third-party entity" responsible may have used it to launch malicious software onto visitors' PCs.
"A third-party entity embedded malicious code into the script, and regretfully, for a period of a few hours (from roughly 9:00am PST until 2:30pm PST), this malicious software (which we believe we have identified as a Trojan) may have made its way onto your systems," a newsletter to fans explained (thanks Joystiq).
"The faith and trust of our fans is of the utmost importance to us, a responsibility we don't take lightly. As such, we are deeply troubled by this development, and we are now working to repair and restore the website."
The publisher advised anyone who visits the site (which is still down as of Monday morning) to run their antivirus software just in case.
Or, if none of this applies to you, you could just read about how much we love Persona 4.