Yummy Yum
Yummy Yums are monsters found in the Candy Vaults in the offs of Mutanous Malaise. Yummy Yums are found inside a Bag o' Yummy Yums and are usually accompanied by an Overthrown Keeper of the Candies. They are fodder monsters, which means their health is very low. There are four main types of Yummy Yums: the Red Yummy Yum, Blue Yummy Yum, Green Yummy Yum, and Brown Yummy Yum. They differ in their appearance and their attack.
There also seems to be a fifth type of Yummy Yum. It is rainbow colored and will not attack. However, it will attempt to unlock the gate to the Overthrown Keeper of the Candies. It will then vanish.
Red and Green Yummy Yums are ranged attackers that shoot balls of colorful energy. Their range is fairly short. Blue and Brown Yummy Yums use melee attacks by jumping on top of you. There are usually between 5 and 10 Yummy Yums in a Bag o' Yummy Yums. Once defeated, they will drop a Yummy Yums Candy, which can be given to Rose or Dorcas for the quest Candy Run. There are usually between 40 and 50 Yummy Yums per Candy Vault.
As an added note, Yummy Yums are strangely reminiscent of the "notes" from Sitar Hero.