Hall of Infinite Doors

You head right, into the darkness. Even though you can't see your hand in front of your face, you feel better now that you've distanced yourself from the ethereal glow.

This feeling of safety lasts right up until a shrill, echoing howl resonates throughout the corridor. The howl is followed by thudding footprints, and you soon find yourself staring at a hideous, glowing beast. It's a four-legged snarling nightmare, and it's looking straight at you.

Do you know its weakness?