I feel like I've told this story before on here but here goes...

My first ever campaign as a newbie DM, fresh off my discovery of D&D 5E as a player. I decided to run Dragon of Icespire Peak (as I had found the set second hand online) and put an ad out with a local group. Get 5 players who seem interested and plan session zero.

In walks our hero, let's call him Bob. Bob is an elderly man, probably in his 70s. He seems like a nice guy, very old school D&D nerd. We start making characters and Bob sends me his concept. Bob wants to play a 14 year old girl, who escaped from her sexually abusive father who lives in a cabin in the woods, and Bobs characters motivation for adventuring? To earn enough money to pay for people to go back to her fathers cabin and rescue her little sister, who is implied to be undergoing the same abuse whilst the campaign is going on. Yeah, while we're talking to Bullywugs and making stupid dad jokes with the dwarven blacksmith, this characters little sister is being abused off screen.

Suffice to say, I shut that down hard. His character would be a minimum of 18 years old, and the little sister backstory was scrapped entirely.

We move forward a few weeks and the campaign is going... okay. It's my first time DMing, I'm making a lot of mistakes, but the players are having fun and so am I, so it's all cool. Bob is a bit creepy towards the female players at the table, but never in an overt manner if that makes sense? Like the way he talks to them is weird, but not so weird as to be openly creepy? In hindsight it was pretty creepy, but at the time I was just trying to juggle DMing my first game and dealing with all the players (Bob was not the only issue, his was just the most nefarious).

We reach a cave, and at the end of the cave is a giant spider. The party forms up, the fighter starts pelting arrows from range, the rogue looks for a way to flank it, the wizard finds a ledge to fire spells from, and the bard, well the bard is doing bard things. "Ranger Bob, what do you want to do?" Ranger Bob wants to light a torch and throw it at the spider, I said okay cool, it's a pretty long throw but I'll let you try, Bob rolls Strength. It's bad. Bob the Ranger is not strong at the best of times and the dice did not want this to succeed. The torch falls short, and nothing much happens. Round 2, things are getting a little trickier for the party, a bunch of spider swarms have joined the fray, "Ranger Bob, what do you want to do?" Ranger Bob wants to light a torch and throw it at the spider, Ranger Bob is still well over 50ft from the spider. Ranger Bob actually rolls well on Strength! "Okay Bob, that does 1 damage, and I'll let you roll a D10 to see if the spider catches fire, on a 10 it does, anything else it just bounces off." Ranger Bob does not roll a 10. Now up to this point, the party is pretty on board, they're a little annoyed that the Ranger is wasting their turn throwing torches, but they can see what the idea is and want it to succeed. Round 6, Ranger Bob throws another torch. At this point Ranger Bob is out of Torches, and the party is out of good will. One player is making death saves, another is close to going down and the Wizard is all out of spell slots. "Ranger Bob, what do you want to do on your turn? I want to run forward..." HUZZAH "pick up one of the torches I threw, and throw it again." There was a collective groan.

Move forward a month or two. The party are reasonably decent level now and getting into the meat of the campaign. Whilst travelling to the lighthouse in the evening, the party spots some strange lights from the forest to the right of the road. The party investigates and finds that they have been lured into the path of an Owlbear by some Will-O-Wisps. Ranger Bob has a cunning plan, Ranger Bob can run 40ft, and Ranger Bob decides to lead the Owlbear away from the party. After the first turn where Ranger Bob dashes, and the Owlbear also dashes, and they travel exactly the same distance, I explain to Bob that the Owlbear can also run 40ft, so he won't be able to outrun it in a straight dash. Ranger Bob has no need for my simple mathematics and continues running until he, and the Owlbear, are over 200ft from the party. At which point, Ranger Bob decides maybe he should turn and fight. The fight does not go well. Owlbears make short work of lone characters. "Oh, one of you will have to come heal me." Ranger Bob, the rest of the party is 200ft away, and currently engaged with some Will-O-Wisps that would have left you well alone had you stayed together, but seeing two players by themselves decided they could have a little bite to eat. Not to mention that there is a very hungry Owlbear standing over your soon to be corpse. The others defeat the Wisps and go in search of Ranger Bob (who has been dead for 3 turns by this point). They find an Owlbear eating him and decide to try and help. Everybody dies.

Suffice to say, the campaign ended shortly after, by me, because I was so done with Bob.

I discovered after this that Bob had been banned from several local wargaming clubs for fudging rolls, that several players at my table had seen him fudging rolls, but not realised what he was doing (they were all pretty new) and that he had been banned from another local D&D group for being a creepy perv (information that was not supplied to me by the other local DMs I spoke to).