This story comes from one of my first experiences with D&D while working at a summer camp as a teenager.
I was a level 5 Ranger in a 13 person party on a massive dungeon crawl through a level 8 dungeon (us being 13 people made up for our being 3 levels lower than we should have been). The party was comprised almost entirely of power builds, we had 2 half-ogres for crying out loud, and so I was a bit out of place as a basic Elven Ranger. During character creation when I had the option to choose my starting equipment I took a longbow and a whip as my secondary weapon. The idea I had was to use the whip defensively when appropriate, but at the time in 2.5E the rules didn't really have a mechanism for that or at least not one that I knew. I wasn't very useful in fights but I served as the group's pathfinder as we didn't have a rogue. Unfortunately given our profusion of ogrekin the party got lazy and dumb at one point and decided to simply bumrush rooms instead of allowing me to scout, which worked decently well for a bit.
There was even a hilarious moment where one of the half-ogre players rolled a natural 20 to kick down a huge locked door and then confirmed a crit roll, causing the entire door to fall on and smush the beholder floating on the other side ready to deathgaze us. I feel that I should note that the GM had given us 3 continues as a party if we got TPK'd, which didn't help with the lack of caution much but we were the staff members of a Boy Scout Camp and we had 10 weeks over the summer to grind through the dungeon and didn't want to have to reset (the thing had over 150 rooms, it was insane). And so after a few weeks, we reached the fateful night which became known as the stalactite incident. We reached a fork in the dungeon and had to decide whether to go through a forbidding door or to go down a well-made stairwell.
As usual, I offered to scout ahead. As usual, the ogres simply ignored me and decided to start walking down the stairs. 16 year old me sighed and went along with it.
Once the entire party was on the staircase we saw that at the bottom there appeared to be a well lit room, which was odd as the rest of the dungeon wasn't all that well lit. This dungeon was once a dwarven city but the dwarven faction was evil, I don't remember the details as it was 20 years ago (god that's depressing to say), and the rest of the players got excited at the prospect of encountering something other than more monsters.
Something struck me as being off about the situation and I asked to make a perception check to see if I could notice anything. I rolled well and was told that the staircase was growing warmer and that it smelled like the inside of a forge. I started to warn the other players but they misunderstood and thought we were going to be able to loot a dwarven forge and like a bunch of Leeroy Jenkins they started to charge down the stairs past me, which of course set off the trap. A loud "clunk" from under the staircase followed by the sound of moving gears was the only other warning we received before the staircase rearranged itself into a steep slope. The fact that the gm had described just how smooth and well made the stairs were took on new meaning as we all slid down it, straight towards the giant pool of lava…
The stairway was a trap built by the ancient dwarves to kill anyone stupid enough to think that looting their forges would be easy and literally led to a big pool of lava they had used to heat the forges, and which as the staircase was curved provided the illusion of a well-lit room from above.
I was still at the head of the group to detect traps despite being shoved along too quickly to actually do so and my warnings being ignored, and so I was the first one to see the coming precipice. Thinking fast I grabbed my whip and tried to "Indiana Jones" myself onto one of the stalactites hanging from the cavern ceiling. I rolled well enough on my dexterity check to pull it off and hung dangling above the pool of lava.
I was excited to have pulled off something cool and dramatic as up until then I had barely managed to do much of anything in the campaign given our party's profusion of spellcasters and power builds. Unfortunately, I hadn't factored in the survival instincts of the rest of the party screwing things up. The next player was one of the half-ogres and as he also didn't want to die he rolled a dexterity check to grab onto me, and he passed.
The player after that was the other half-ogre who likewise didn't want to die and rolled dexterity to grab onto the first half-ogre, and passed.
One by one the entire party rolled their dexterity checks to grab onto the person before them's legs, and one by one they all passed.
When it was all said and done the entire party was dangling in a humanoid chain from my ranger's legs above the pool of lava. We all began celebrating having narrowly pulled off literally bumbling to our doom, until the GM turned to me and said: "Perform a Strength check."
I was an elven ranger built to have high Dexterity, Wisdom, and Charisma and I had specifically chosen a melee weapon that didn't use strength bonuses to not suffer any "opportunity cost" for not having one. I had used Strength as my dump stat, and suddenly I was hanging from the ceiling while trying to hold the additional weight of 12 other characters, two of whom were fricken half-ogres!
Our GM did say that if I rolled a natural 20 I would somehow find the strength to pull it off, and so for the first time in the campaign where I was the youngest player the entire party was focused on my roll. Up until then, I had been the easily ignored background character what with my lack of high damage output or any of the other crazy gimmicks the other players had and suddenly I was in the limelight for the first time. For the first time, everyone was depending on me and my quick thinking was the only thing that could save us all. Sadly it was also the last time as I did not roll a natural 20 and we all fell to our extremely painful but mercifully quick deaths.
With the first of our 3 continues spent we decided to take the other door at the fork and we left the "stalactite incident" behind us. It was one of my first D&D campaigns and the first one that was more than a one-shot, and while we never did finish the dungeon somewhere around room 115 after suffering our fourth TPK to some sort of horrifying sentient flesh wall which absorbed party members and used their powers against us it was still a lot of fun.
From it I took away the following life lesson: Never use strength as a dump stat because you never know when you'll have to literally hold up the entire party by yourself.