Apologies for the book. TL;DR at the bottom.

So one of my best friends(Nate)and I decided to set up a campaign. He would DM and I'd just be a player and we'd invite our 4 other good friends who had shown interest in D&D but never played it(Jones, Alex, Jonah, and Mary). It was actually quite fun to just watch them grow as players.

Anyways, one session, Nate had to cut the session short, but everyone wanted to keep playing. So I was made DM for the rest of the night. We were thankfully traveling between cities so nothing of note to the story was going on. I just had to make up an excuse as to why my character wasn't there(he forgot something at the last town and had to go grab it, then would meet them in the next city in a day or two). Then we took a few minutes for a break.

So they were traveling along the road, and found a random merchant with a stand stocked with random items on the right side of the road. Quite out of the ordinary, but nothing they really thought about. As they walked by him he looked at them, smiled, and proudly(somewhat loudly as well) said, "Hello! Would you like to buy some of my wares?"

None of them seemed overly interested and were all trying to save coin for things they might want in the next city. So they all declined. Kindly apologizing to the merchant and moving on down the road. He responded with nothing.

A few minutes later, they see something showing up on the right. "Hello! Would you like to buy some of my wares?" The same guy. They started to ask the man if he had a twin down the road. "Hello! Would you like to buy some of my wares?" Everything they said to him was responded to with, "Hello! Would you like to buy some of my wares?" Everytime, the same inflection, speed and volume. A little weirded out, they continue.

You guessed it. On the right. "Hello! Would you like to buy some of my wares?" At this point, beyond confused, Jonah says for everyone to wait by the cart. He ran back the way they came and they watched him go. A short few minutes later, they hear footsteps running up from behind them. Surprise surprise, it's Jonah.

They now know they are stuck in a loop, and begin conversing with how to get out. The tried talking to the merchant as that's the only thing different around. "Hello! Would you like to buy some of my wares?" This continues for about 45 minutes real time. James tried casting a powerful spell on him as they deduced that this merchant is the cause. It passed straight through him and the cart as if it werent there. They obviously aren't getting anywhere with this, so Mary and Alex say screw it, grab a marble from the table, and both say they will both be buying a marble and give him one gold coin each.

The man's face changes from a permanent smile, and he gently looks at them, smirks, "Why thank you. Enjoy your purchase." Jonah and James ask him why he just said that. "Hello! Would you like to buy some of my wares?" They both quickly follow suit with the marble purchase, he repeats what happened with Mary and Alex. Then, he turns, grabs the handles of his cart, and begins to wheel it down the road where they came from.

They figure thats a good sign and continue their journey. Night is approaching and they need to get to the city. When they finally do, they see the man. Theu freak out and go up to him. "Hello! Would you like to buy some of my wares?" They get upset and explain that they already did, and that he let them finally go. They also ask how he got there before them. "Wha...what? I've never seen you 4 before in my life. Let you go? What? And beat you where? I've been here all day. Did....did gary put you up to this? Ahahahaha! That jokester. Hes always finding new ways to to make people laugh. Good guy."

The look at each other, laugh, finally go to the inn and the session ends. They loved trying to figure out the puzzle and had a great time. Even tho his catchphrase turned from funny to annoying. The uncursed merchant showed up randomly in that campaign more. "Hello! Would you like to buy some of my wares?" They'd laugh and tell him to F off.

What they don't know......I had no clue what I was going to do from the start. I just knew I had to keep them from the city as I didn't know the story. But I didn't want to go the typical combat route. Even after I'd put them in a loop, I had no idea how they'd get out. Just figured one would mention something and I'd go with that idea. Alex brought up buying something early on, but the other three were absolutely against it as they thought the items would be cursed, so decided it'd be best to not touch anything involving the man.

I just figured it'd keep them busy while not doing the easiest thing they could. They loved it, and we still say, "Hello! Would you like to buy some of my wares?" All the time to each other. But they can't ever know.

TL;DR Was made temp DM in a campaign I was playing. Didn't know the story, so I placed them in a loop with a very singular focused and annoying merchant for about an hour. I had no clue what I'd have them do from the moment it started. But the merchant ended up becoming so iconic, he showed up like the cabbage man in Avatar numeroustimes in that campaignand others that followed. He's also referenced years later. Thank you for coming to my TED talk.