A few years ago a bunch of work friends and I had a Pathfinder and DnD group where we would switch DMing games, but we had one player in our group who consistently would bring these sessions to a flaming wreck of a close because of excessive trolling. The session that broke "the DM's back" so to speak was when my friend Kevin was DMing and we always played with one rule in all our games -- "Actions have consequences" -- be it things said out loud without indicating if it was in character, out of character, or actions by players. There were five of us playing this particular campaign. I was a Half Elf Gunslinger and I was joined by an Elf Cleric, Human Cavalier and Bard, and our troll who was playing a half elf rogue. Early on in the campaign, his play style was causing some friction such as purposely setting off traps and saying he was "learning their mechanics," or after an encounter, announcing he would either take all the loot available or throw a vial of acid on it, destroying it so we could not attain it. At first, we shrugged it off as the Rogue being a Rogue. You know, under the excuse that we were all just getting to know each other in character and our reasons for meeting. And so we just went with it. Alas, it was all in vain, as I will highlight the main story now.
Word of our adventures had reached the ears of a King whose lands were in danger of being overrun by their neighboring kingdom. That kingdom had recently invaded the surrounding lands in the name of "One King, One Land" and was well known to be executing dissidents after the wars were over. The king spoke on behalf of several other nations and asked us to stop the invading king, for which we would be rewarded justly. After the meeting our Cleric had gone to the local temple to verify this tale, while we found an Inn to rest and gather information. The cleric returned and told us atrocities committed at the hands of this king by the priests who spent days burying the dead and tending to the wounded refugees. The Bard also caught wind of rumors from refugees as he was playing for coin on the street, but our time was cut short when the rogue was caught trying to steal from the refugees and then failed his bluff to the city guard. At this point the DM was becoming a bit concerned with the Rogue and had asked him in sidebar what his motivations are, his response being, "I am just being my character. It’s nothing big.”
He was placed in jail and when word had reached our characters about this the Cleric spoke up, "Leave him. He is a stain on us and I will not suffer him any longer." The Cavalier was in agreement, but the bard was on the fence, stating that the rogue should be given the chance to redeem himself. But my character was the deciding voice, "He is going to be a liability to us on this job. He is stealing from the people we are trying to help and even I can not abide by this."
A little background here: My character is a sniper in essence, having spent his time roaming battlefields as a gun for hire, but had limits as to what jobs he would take. So he was Chaotic Good. The rogue was sitting the whole time at the table, staring daggers at us, and seemed to really not like my answer. He had asked to see the DM privately and a 15 minute pause began. After the pause, the rest of us began our plan of attack. The bard had heard that the rival king's army was camped at the border of the two countries and was to begin their invasion in two days. We would make our way to the camp where I would set up at an elevated position and try to assassinate the rival king when the armies met all while the Cavalier, Cleric, and Bard were in the employing king’s camp as sell swords. Before we left we did one final supply run and my character happened to find a vendor selling potions and whatnot. He gave me four potions for free, stating, "For your fight ahead."
I used a sense motive as I asked him what he meant but my roll only got me, "The Bard was singing of the battle to come last night."
What I did not know and what the rest of the group did not know was that the sidebar the rogue had with the DM was about getting back at the party for not coming to get him. What he did was roll separately to escape the jail cell and disguise himself as the potions vendor, knowingly giving us four poisoned bottles that could kill us if we failed 2 save rolls. The DM cautioned him to think this over but allowed him to go ahead stating, "actions have consequences."
Fast forward to the battlefield. The party had arrived the day before and was greeted in camp by the commanding general. He told us of recent troop movements and warned that they had been hit with scouts earlier, indicating the attack would be imminent. No sooner had that been said than a horn sounded and a group of light cavalry was spotted approaching. The Cavalier got on his horse and joined a group of riders going to intercept. I had also offered to provide cover. The engagement lasted a few turns, but I ended up taking a few hits due to some of the light cavalry having crossbows and knocking me down to 4hp.
I decided to use a potion before heading back and here is when it went to hell. The DM asked me to roll a D6.
"Huh? What’s up?" I asked as I did this. It was a 3.
The DM looked at me for a moment of not speaking and I could tell that something agitated him. "You drink the potion and you feel nothing at first, then you double over in gut wrenching pain."
The rogue at the table starts to laugh and I immediately realize what has happened. Out of character, I yell, "Dude! what did you do?"
He looked at us and feigned innocence. "Me? I didn't do anything, but my Rogue is teaching the party a lesson about loyalty."
The other players at the table became visibly upset with him and asked what he was thinking. He then went on to tell us that these games are boring and he wanted to spice them up. Kevin had remained silent the entire time but I could tell he was on the verge of exploding. At this point, the Cavalier rode to my position and saw my character doubled over. He rode back to grab the cleric but by the time he got back, I failed my two saving throws and my character was dead. I had to excuse myself from the table as I went to regain my calm.
This was only a game but the rogue took it too far. I came back after 5 minutes later to find out that the Rogue somehow had reappeared in camp and passed his bluff telling everyone that he was let go.
The tension in the room was thick as the Rogue then went over to my body, looted it, and took my rifle, saying, "Hmm How hard can this be? We kill the king and get our pay. I will do it."
The rogue had ZERO skill points in firearms, so he would be shooting at a major disadvantage, but he insisted he do it. The day of the battle arrives and the DM throws a curveball. The king who employed us is taking the field to challenge the rival to single combat. The rest of the party is trying to figure out what to do when Kevin calls out, "Make a perception check" and everyone realizes to their horror that the Rogue is missing. He had snuck off during the DM's monologue for the kings and had taken up position overlooking them.
The bard tried to speak up "Uh has anyone seen the Ro--”
"I pull the trigger and fire!" The rogue yells out before anyone can get a word in and drops his dice on the table… a 5, but as he was at a penalty he had to roll a nat 20 so this was the equivalent of a negative 5. Kevin just sits there a moment before slowly folding up his DM screen and speaking, "Having not gotten the feel of a rifle that was customized to be used by its original shooter, you misaligned the shot. The bullet sails across the field and into the back of the first king's head, showering the other in blood, brain, and bone. All eyes now turn to the party.”
"They killed the king! Assassins! Betrayers!" With those words being said, the army descends on the players, killing them and allowing the rival king to claim the land. Killing and murdering.
There was a dead silence in the room before the DM looked at the troll and said, "I want to speak to you privately outside.The campaign is done, guys. I am sorry."
It was about a month before that I got a call from kevin letting me know that the troll, even though he was a friend, was no longer welcome at ANY of our games anymore and we set up a new DND Campaign a week later. It still blows my mind to this day why he did what he did. If you were not having fun, then why ruin it for everyone else and then purposely sabotage it for the DM?