Marshmallow is the secondary tritagonist of The Annoying Orange Series. He is Midget Apple's best friend.
Usually, Marshmallow is not angry or frustrated. However, in the episode Best Fiends Forever. He got very angry because Grapefruit burns a picture of Marshmallow's favorite unicorn, Princess Butterfly Kiss. He then proceeds (offscreen) to attack Grapefruit which caused the house to explode. This side of his personality would become more common in later episodes. he often laughs and has the same sense of humor of Orange. He has a funny laugh that goes, "Hehehehehe!" and "Yay!". Orange and he seem to be close friends. Orange doesn't annoy Marshmallow at all. Marshmallow also has a high-pitched, squeaky voice and has the personality of a child (and it is possible that he still is).
Marshmallow is a cheery, bubbly little soul; he is always happy but will instantly switch to the emotion that suits the current problem, it is shown that when he sneezes, magic, sparkling glitters spray out of his non-existent nose. He enjoys "rainbows, puppies and kittens and flowers and Rainbows and clouds and bunnies and rainbows" (as he said in the Annoying Orange meets Charlie The Unicorn Spoof). He is never sad, angry or unhappy unless the situation justifies it. He also has a profession in writing song lyrics, despite the overuse of rainbows in them.
- Although Marshmallow was referred as male in four episodes, Marshmallow's true gender was kept hidden from other characters as well as the audience regardless of comments. However, Marshmallow sometimes did intend to reveal his true gender but always fail to do so.