Milkshakes is Billy's cute pink cat. Milkshakes is seen to be a bit aggressive towards Billy (ex: attacking him for moving him off the TV set). She seems to also dislike Billy's hamster, Mr. Snuggles.
Milkshakes is not very detailed when drawn or recognized. He has pink fur and dotted black eyes, though a color is not specifiable. Whiskers do not seem to be heavily present, and no patterns appear on His fur.
Milkshakes bares an adapted personality stereotypical of a cat, even when affected directly by supernatural powers or brain related powers. He has an aggressive activism towards Billy during most encounters, but can occasionally show a sign of feline affection for him (ex. rubbing Billy's legs casually and purring slightly).
While Milkshakes is aggressive with Billy, usually it is for a good reason, or simply because he is annoyed with Billy. No definite interactions with outward characters, including Grim and Mandy, are seen as being present, or they are simply neutral.
Milkshakes has also been possessed multiple times in the show, once by Grim, Mandy and another time by Book Worm.
- Milkshakes is the only pet to ever truly survive Billy's destructive behaviors with animals. (Billy's hamster technically survived as well, but was emotionally not sound, though it could have likely been due to his advanced age), while Milkshakes maintains a solemnness about him.
- Billy eats Milkshakes' droppings; though that's not really a trivial fact of interest, it is displayed heavily anywhere else in the franchise.
- Only character to ultimately avoid Milkshakes' wrath and pleasurable company all in one fell swoop.
- Mandy possessed Milkshakes to maul Billy as revenge for possessing his body and mind.
- While Grim has been equally as attacked as Billy, he is usually a victim of second hand aftermaths, not the antagonist of the cat itself.
- Milkshakes is one of the characters who took Grim's Scythe in Billy and Mandy's Big Boogey Adventure.
- Grim once possessed Milkshakes, making the cat sing and dance.
- Most minor, or other characters who ever interact or are present with Milkshakes show a neutral bond, but that is more likely due to the simplicity of minor characters, than an actual definition of Milkshakes real being (metaphorically).
- He was blasted by the Jurassic creeps with a laser in toys will be toys.
- Milkshakes was once accidentally possessed by Book Worm after Milkshakes swallowed him.
- Unlike most animals in the franchise, Milkshakes is resistant to effects from supernatural entities. Having survived so many incidents involving Grim's initial blunt power from external sources, Milkshakes is best described as becoming slowly immune to such powers. Throughout the show, Milkshakes slowly showed less fluently visible attributes of being possessed by supernatural powers, or beings.
- The only animal to purposely bear non-realistically colored fur.
- The simplest of all "characters" in the show and least relevant to the story in most cases, though applies indirectly in early story lines.
- Milkshakes is voiced by Grey DeLisle. Who also plays the voice of Mandy and many other characters. Gregg Berger voiced Milkshakes when he was possessed by the Book Worm.