What size shake does not get the mint when substituted for the drink in a Wacky Pack?

The correct answer is Mini because, in the context of a Wacky Pack, certain substitutions come with specific modifications based on their size and contents. When a Mini shake is chosen as a substitute for a drink, it is typically a smaller size that does not include the mint flavoring that might accompany larger shake sizes.

This differentiation in flavors or additional elements based on size is a common practice in menu offerings. In contrast, larger shake sizes, like Small, Medium, and Large, often come with added flavors or inclusive garnishes, such as mint, which are standard for those specific portions and enhance the overall product offering. Therefore, the reason why Mini does not get the mint is that it is seen as a more basic option without the enhanced flavor profile present in larger shakes.