Mystery Man is an email in Prey. The email was added as the result of a "get your name in the game" contest, which was won by Gus Lanzetta (https://twitter.com/GusLanzetta).
See https://bethesda.net/en/article/65eA0nCPQWUkmi8ugkeaEw/prey-i-am-transtar-npc-contest
Transcript[]
| From: | Annalise Gallegos |
| To: | Rory Manion |
| Cc: | |
| Subject: | Mystery Man |
| Does Lanzetta ring any bells? Dr. Gus Lanzetta? What if I told you he worked with us for a week? One week. The week before the entire science staff had last quarter's Neuromods removed. He left his badge in a locker. I had IT look up his account, and it had all been deleted, all but his credentials. Who the hell was he? | |
Location[]
This email can be read on Rory Manion's workstation in Behavioral Biometrics, Psychotronics.