In a toy store, four children - Ella, Daniel, Harper, and Ethan - are looking at different toys. Ella wants a pink teddy bear, Daniel wants a yellow race car, Harper wants a purple doll, and Ethan wants an orange robot. Their parents tell them they can only choose one toy each, so they put their selections in a shopping cart before going to find their parents. While they're gone, another customer accidentally takes their cart and replaces it with an identical one containing different toys. What will happen when the children return to the cart? How might they feel or react?
Provide a brief response.
When the children return to the shopping cart, they will likely find it filled with toys that are not the ones they originally chose. Since Ella was looking for a pink teddy bear, Daniel a yellow race car, Harper a purple doll, and Ethan an orange robot, if the toys in the replaced cart are different, they will immediately notice that these are not the items they were excited about. 

The children may feel confused at first, as they might believe they've come back to the wrong cart. Once they realize the cart has been switched, they could feel upset or disappointed because they each had their hearts set on a specific toy. They might react by looking around the store to find their original toys or by asking a store employee for help. The situation could lead to feelings of frustration if they can't locate their chosen toys quickly, especially if any of those toys were the last ones on the shelves or if they had built up emotional anticipation for playing with them. Depending on their personalities and past experiences, they could also show understanding once the situation is explained, but the immediate reaction would likely involve some degree of upset or disappointment.