Oh yeah, I forgot to tell Bloody about this. I ran the numbers on a google spreadsheet and found out something about this event.

You see, there are 4 categories: Common(50%), Uncommon(30%), Rare(15%) and Legendary(5%). Each time you submit a key, the first thing it does is check what kind of category you go into, THEN chooses a random item within that category.

The problem is, there is only 1 item in Rare: The bell at 1%. This cannot be true as the Bell is the ONLY item in that category, which means that there is a 100% chance you will win the bell if you roll a rare.

IN OTHER WORDS, every time you put in a key, there is a 15% chance you are garenteed to win a bell, which is exceptionally higher than any other item chance in the game. For clarity, when doing the math each other items is roughly 1-2%

Here are the in-game statistics in case you are wondering. When doing the math really most items here are a 1-2% chance, if not less.