This is a potion shop located at what used to be a dead end hallway.
Here is the list of it's products:
- Fortify Perception
- Fortify Strength
- "Happy" Potion (commonly used to give interns a false sense of happiness)
- Dragon's Breath
- Popcorn (salted or unsalted)
- Kettle Corn
- Parmesan Popcorn
- Spicy Popcorn
- Mangos & Mango Juice
It's manned by a man in a red & white striped suit and a gas mask. The room behind the shack is the teleporter room, and also serves as a shipping dock for the shop.
The original post describing it can be seen here.