That Panther From the Corner

You are walking down a long and slanted hallway, whereas the roof seemingly gets higher the farther down you go. In a giant, complicatedly maze-like, and distastefully pink castle; you must find your way out. But once a door opens, the one behind you shuts tight. As they say, no place to go but up.
However.
There might be a matching purple panther following you. And that creature might be extremely long and slender, not at all welcoming like your memory of the words. He may also, just a slight chance, be draining your sanity- bit by bit. What will you do when you reach the very top of the castle?
Heck, don't ask me. Not even I know where this is going.