Third-floor corridor

The third floor corridor on the left hand side was out of bounds in 1991-1992 because of the dangerous obstacles guarding the Philosopher's Stone, that Harry and Hagrid had picked up from vault 713 at Gringotts before the start of term.

Fluffy

The first obstacle guarding the Philosopher's Stone was the three headed dog Fluffy, who was bred by Hagrid and positioned on top of a trapdoor. The way to get passed Fluffy is to play music, Quirinus Quirrell had bewitched the harp to play and Harry played his flute that Hagrid gave him for Christmas.

Devil's Snare

The second obstacle planted by the Herbology teacher, Professor Sprout, when you go through the trapdoor you instantly land in the plant and the way to get out of it is to relax. If you don't relax, it will begin to tangle up to your neck and atempt to strangle you. A simple Lumos Solem will burn it.

Winged Keys

The third obstacle is the Winged keys that are charmed to fly by Professor Flitwick. There are brooms in the room and the correct key must be caught in order to unlock the door and proceed into the next chamber.

Wizard's Chess

The fourth obstacle is a life sized Wizard Chess game enchanted by Professor McGonagall. The only way to get past it is to play your way through as the black pieces

Troll

The obstacle from Defence Against the Dark Arts was a troll.

Potions

Danger lies before you, while safety lies behind, Two of us will help you, whichever you would find, one among us seven will let you move ahead, Another will transport the drinker back instead, Two among our number hold only nettle wine, Three of us are killers, waiting hidden in line. Choose, unless you wish to stay here for evermore, To help you in your choice, we give you these clues four: First, however slyly the poison tries to hide You will always find some on nettle wines left side; Second, different are those who stand at either end, But if you would move onwards neither is your friend; Third, as you see clearly, all are different size, Neither dwarf nor giant holds death in their insides; Fourth, the second left and the second on the right Are twins once you taste them, though different at first sight - Riddle for the Potions obstacle

The last obstacle guarding the stone is the Potion Riddle and you have to figure out which potion to drink to get either through the black flames to the Philosopher's Stone or back through the purple flames