The Secret Triwizard Challenge

You yell, "Incarcerous!" and fling your spell at the spider. The spell deflects off the ropes already binding the spider and ties more ropes onto those ropes. That... certainly wasn't good.
The spider breaks free, lunges at you, and tackles you to the ground. You can't move your wand hand - actually, you can't move anything at all. That spider has you completely stuck beneath it, so there's nothing you can do as the spider dips its head down to bite your head clean off-
At the last possible second, two of the monitors flying over the maze cast Flipendo on the spider, flinging it away from you. One grabs your arm, pulls you onto their broom, and flies back into the sky. You're alive!
...but frankly, you'd rather be eaten by a giant spider than admit you lost the race.
YOU LOSE!
End Of Story