For point of reference for future posts: At the bend of this hallway, characters would be one-half their normal size, and characters at the end of the hallway are one-twentieth of their normal size.
Feel free to adjust your positions and sizes accordingly on Owlbear Rodeo if what I have originally isn't quite correct. ^^"
As Brutrumukk, Jub, Aurora, Zavakri, Vansel, and (maybe) Gabriel enter the tunnel, they first notice a moldy scent hangs in the air in this dark, L-shaped hallway.
As they continue walking down this hallway, the party start to feel this strange sensation wash over them. It's not painful by any means, but it is noticeable and foreign. Jub, Brutrumukk, and Gabriel would recognize this feeling from their time at the Pixie Kingdom: They're shrinking down! The process is slower than before, but this is definitely what's happening.
As the conga line continues, the people in the line chant along with the word conga, "How low can you go? How low can you go? Limbo!"
Upon reaching the end of the hallway, it would seem as though their way is blocked by solid wall.
Aurora would be able to notice that there is a mouse hole here. It's blocked by a door.
The door is barred on this side by a steel needle...
Mini Bav rolled a 12 on their Wisdom Saving Throw against Tasha's Hideous Laughter. I believe that meets Jub's DC and succeeds. It is no longer laughing and it is retreating.