In this guide, I show where I find all 5 foxes in Deltarune Chapter 5, how I open the locked door after collecting them, and how I obtain the pink coin that can be used to buy the MysteryKey.
All Fox Locations
To reach the final fox behind the door, I first need to locate five hidden foxes across the nearby rooms. Some of them require me to chase the correct target, inspect paw patterns, or move Terakotas out of the way.
Fox 1
For the first fox, I enter the first room and chase it around until I can catch it. I may also encounter a Terakota while moving through this room.
After collecting the first fox, I can continue into the second room.
Fox 2
When I enter the second room, I find a covered area filled with several fox-shaped figures. I stand on the nearby button to reveal that most of them are bouncing rocks.
To obtain the second fox, I need to identify and select the real fox among the moving shapes.
As an additional detail, I can sometimes find other characters among the rocks, including Toby, or the annoying dog, and Seth.
Fox 3
For the third fox, I leave the main room and follow the trail made from paw patterns. I can also find what appear to be Flower Dollars at the end of this path.
I continue along the trail until I reach the wavy paw pattern. The fourth paw in this section is actually the third fox.
Fox 4
To find the fourth fox, I return to the first room and move toward the top of the area. When I reach the Terakota shown below, I push it aside to reveal a hidden door behind it.
After entering the hidden area, I find Yellow putting on a sock. Yellow screams and then transforms into a fox that is also wearing a sock, referencing Chapter 3.
Fox 5
For the fifth and final fox, I return to the first room once again and focus on the bottom-right row of Terakotas.
I throw the Terakota positioned before the last one into the void. This is the third Terakota in that row. After removing it, I can collect the fifth fox.
Opening the Door
After collecting all five foxes, I can open and enter the previously locked door.
Inside the room, I find one more fox. I approach it and interact with it to receive the reward.
After interacting with the final fox, I receive a pink coin that can be used to buy the MysteryKey.