Made for the monsterfriend project on Tumblr.
While not very intelligent, Marshmellow is intuitively skilled at channeling magic to even actively absorbing it from its environment during times of stress. Keeping it content is key. Usually takes on a comfortable four legged form that is about 5 feet tall at the withers, weight is too variable to determine.
It will also eat anything small and vulnerable when hungry enough. Do not leave it alone with small children or pets.