Paranoid Gun Owner
The Paranoid Gun Owner passively (and involuntarily) kills anyone who targets it during the Night.
Paranoid Gun Owner is very commonly abbreviated as PGO. Controversially, it has also been called Army Veteran.
Paranoid Gun Owners are more often Town than scum.
The Paranoid Gun Owner shares some similarities with a Bomb.
Uncommonly, a Paranoid Gun Owner is also Bulletproof (they shoot first before they're shot).
Use and Power
The Paranoid Gun Owner is a very swingy role, as in addition to killing the Mafia if they target him, it will indiscriminately kill Cops, Doctors, etc. As a general rule, PGO is an anti-Town role because it is more likely to kill Town power roles than scum in all cases except when there are no other Town power roles (in which case it is functionally a Bomb). When town, it is typically considered a negative utility role (and as such is often claimed right at the start of day 1 in order to minimize its impact.)
Since the PGO is not informed of who they have killed, this can also obscure how many actual killing roles are present in the game.
Note that whatever powers were used on the PGO still take effect – thus, if the Mafia choose to kill the PGO, the PGO will still die along with the Mafia performing the kill. However, if an action is blocked, most moderators will normally treat the action as not having happened, so it won't hit a PGO (and thus cause the user to die) even if it was trying to target the PGO. However, this is not quite a universal rule, so it's worth checking with your moderator if the interaction is relevant.
The ideal play for a PGO is to get targeted by the Mafia, while not being targeted by any Town power roles. However, safer play is to claim directly -- this keeps other Town power roles safe, but also ensures the Mafia will not target you. Note that by claiming, you are opening yourself up to potentially being policy eliminated at some point during the game.
A very risky strategy is to hint at a power role, causing the scum totarget you, and, as a 1 for 1 trade with scum is in the town's favor, you will have helped the town..