Last night's session was going to be a standard "storm the evil temple" night. Instead 2 of the 6 party members surprised the rest by waylaying one of the other characters.
The why: she's wearing a crown which contains the spirit of an ancient evil archmage. She's been using clearly evil spells (necromancy, possession) in fights, but only to ever help the party. The character isn't evil but is pragmatic and doesn't understand the source of the power she's tapped in to. Ever time it comes up she evades the questions. They were super suspicious.
The what: they hit her with a suggestion "let us tie you up." It works, but that does nothing to stop a mentalist from hitting you with a whammy or twelve. Lots of mind control attempts back and forth. Nobody is using anything lethal. The only actual hit point damage was via pain / agony spells.
Eventually she gets tired of being ganged up on. She lets the spirit out "just a little" and it uses higher level spells to try an get them off of her. That doesn't work, though they do finally see the crown which she's kept hidden. This comes complete with black flames dripping from it and flickering shadows in her eyes. It spooks the party and one of the "less cerebral" characters gets the idea she should try to shoot the crown off with an arrow.
She's been trying to explain that she has the entity held in check but that dire
doodoo happens if it gets free so they should leave her alone. She points out she's never done anything but help the party hunt down and destroy the cult of Morgoth they're fighting.
The hitting of the fan: Arrow flies at head... She says "
fudge it." Bad guy is let free. PC's psyche is trapped in a cage inside her own soul. Party member who shot the arrow is possessed by a Type III demon (save every 10 minutes). Party member who used suggestion is hit with permanent paranoia. Hilarity (at least IMO) ensues.
I gave the player the demon's personality traits. She's kinda slow and didn't really understand what I meant for about ten minutes, thinking she now had the powers of a demon for her normal character. In the end she got it but couldn't figure out how best to roleplay an entity which has been trapped in an eternal void for millenia and is now experiencing sensation for the first time in a loooong time. Since she was already wracked with pain from the agony spells I had it go buck wild mixing sensations. She dropped to the ground and ore up some grass. One hand scratched painful furrows into an arm while she gently tickled the other arm with the grass.
Lady with crown breaks free and pushes the archmage back down. The demon is still three but isn't violent so they distract it with a myriad number of sensations and toss her in a cart to take and find an exorcist. She breaks out of it a few hours later.
The aftermath: Now the PC with the crown has left the group but still needs their help to storm the temple. The archmage has offered her power and revenge in exchange for tearing down the interlopers who has coopted his old fortress. She uses Necromancy to create a ghost and sends it out to be an emissary and attempt to start a dialog.
That was much more interesting than a couple of lines of temple soldiers guarding a couple of priests and some archers.
Up until now the crown was basically an intelligent item. Now I get to actually stat up the mental traits and powers for this archmage. I foresee it braking free again and would like to be better prepared.