well I hope you don't end up .ore confused:
This person is referencing a humorous trope often found in tabletop role-playing games (TTRPGs) like Dungeons & Dragons (D&D). The phrase "3 Kobolds in a Trenchcoat" refers to a situation where three small creatures (kobolds) disguise themselves by stacking on top of one another and wearing a trenchcoat to appear as a single, normal-sized individual. It's usually played for comedic effect.
In the context of a dungeon, this could imply:
They encountered a disguised enemy or ally.
It's a playful teaser for a campaign, hinting at something unexpected or comical happening in the game.
"Oddly a teaser" suggests this might be a hint or setup for an amusing or tricky encounter in the future!