Your Favorite Supernatural Being Or Event?

So throughout the entire series, what do you consider your favorite supernatural being or if that's not the case, supernatural event that has occurred within the past few games.

For me it goes to.....

The Great Worm.

It is a truly creepy and unstoppable demonic force that sustains itself off of human souls. Those poor souls devoured by it are then slowly digested. For me it marks the most evil and scariest creature we've discovered in the Metro so far.