Zappo
Explorer
97. Have a PC killed and replaced by a doppelganger or similar creature, but do it stealthily and don't allow other players to know that. Let the PC's player keep playing the doppelganger. See how long it can go.
IMC, it went on for a couple of months. On top of that, the creature wasn't a doppelganger, but a visage from Dead Gods. Whose illusionary powers are almost limitless, and can Dominate at will. So, every now and then, in critical moments, a character would get dominated and attack the others, and the players would freak out trying to understand who or what did it. They never found out until the end of the adventure.
Not to be pedantic, but the point of the thread seems to be to creep out the players, not to kill the PCs... so I don't know if killer tactics for villains are what we're looking for...
IMC, it went on for a couple of months. On top of that, the creature wasn't a doppelganger, but a visage from Dead Gods. Whose illusionary powers are almost limitless, and can Dominate at will. So, every now and then, in critical moments, a character would get dominated and attack the others, and the players would freak out trying to understand who or what did it. They never found out until the end of the adventure.
Not to be pedantic, but the point of the thread seems to be to creep out the players, not to kill the PCs... so I don't know if killer tactics for villains are what we're looking for...