The Annoy-o-Tron 5000

As you approach the strange machine, Gnorman hobbles out of his hut and addresses you.

"Hello, Tall One! This is my greatest invegntion -- the Annoy-O-Tron 5000! When the dial is turned, it emits low-frequency waves that permeate the egntire Kingdom, causing all of the mognsters to become enraged!"

The device is currently set to level X.

Set the dial to: Level {0 to 10}. Touch that dial!

Notes

Located in the Gnomish Gnomads' Camp, an area only accessible to players who have ascended with a Moxie zodiac sign, this device has a dial which supposedly controls all the monsters in the Kingdom. The dial goes from 0 to 10.
Setting the dial adds that number to the level of every monster you fight.
Setting the dial to 0 yields the following message:

You switch the dial. All of the monsters in the Kingdom breathe a sigh of relief and settle back into their normal routines.

Setting the dial to a number 1 to 10 yields the following message:

You switch the dial. All of the monsters in the kingdom suddenly wince, as though they were being bombarded with waves of concentrated annoyance.

In a Zombie Slayer run, the message is changed:

You approach the Annoy-O-Tron 5000, which appears to be none the worse for wear. Gnorman doesn't seem to be around to tell you how to operate it, but since the only control is a dial numbered from 0 to 10, you can probably figure it out on your own.

Attempting (through possibly unscrupulous means) to set the dial to a number that is out of the valid range yields the following message:

Invalid dial setting. You invalid dial setter, you. Hey, we just got a new dog! It's an Invalid Dial Setter!

You can also receive special rewards if you defeat certain bosses with the dial at certain settings, as detailed below. Click through the individual rewards for more details.

Boss	Setting	Special Reward
Baron von Ratsworth	2	Baron von Ratsworth's money clip
Baron von Ratsworth	9	Baron von Ratsworth's tophat
Boss Bat	4	Boss Bat britches
Boss Bat	8	Boss Bat bling
The Knob Goblin King	3	Glass Balls of the Goblin King can be crafted into Staff of the Soupbone
The Knob Goblin King	7	Codpiece of the Goblin King
The Bonerdagon	5	rib of the Bonerdagon can be crafted into Staff of the Soupbone
The Bonerdagon	10	vertebra of the Bonerdagon can be crafted into Bonerdagon necklace