Let me set the scene, I'm playing a silver dragonborn Paladin of Conquest, with at the time a warforge rogue, tabaxi bard, deep gnome wizard, a shifter blood hunter (who eventually changed his character, then changed again), a half-elf fighter, and our human cleric/monk remember. This campaign takes place in a world where the giants had gone extinct, and our starting location was in a desert. You can probably see where this is going, but it gets better. It begins with us entering the starting town, us travelling in groups of 2. My character, Xextra, did not know this however, and only found that our tabaxi bard was following her for weeks on the day the group met. She said that the reasoning for her following was that my reflective scales could keep most of the monsters of the desert away from her. We eventually meet up with the rest of the group, and our first adventure comes and goes. Dealing with a Dybbuk that had taken a pair of siblings' grandmother as it's new host after killing her and her husband.
The real fun began when the next issue came along. The magical fountain in the center of town was starting to run dry, and it turns out that the magic only kept the water clean, cool, and drinkable. Kobolds that lived beneath the city kept the fountain in working condition, but they stopped taking care of the fountain. We're tasked by the townmaster to investigate. Xextra and our cleric took point, both knowing draconic and being able to communicate with them in their native tongue. We turn the corner and hear a shout from the two guard kobolds that set the running gag into motion.
"MY EYES!" was all the group heard, and then we all collectively remember Xextra was a METALLIC dragonborn in a desert. Her scales weren't just bright, they reflected light like mirrors, he was a walking beacon in the desert, and that didn't mix well with a Kobold's Sunlight Sensitivity. We struggled somewhat at first talking to them because every time they looked at me, their eyes were cooking like eggs on a frying pan. Eventually we get inside as the chief invites us in.
And so, afterwards the joke began. Every time enemies find us randomly in the desert, we would joke that Xextra was the reason, and any stealth checks in daylight that she failed or failed around party members, her reflective personality was brought up as how we were spotted. And every time the group returned to the kobolds that we helped come to an agreement with the town peacefully, the DM always mentioned how they had to shield their eyes when Xextra came by.
Unfortunately, things came up and I had to leave the group, but that game had my first running joke in a campaign ever, and I will never forget it.