Plot hole: It takes less than 3 minutes to fill the house with water using a mere garden hose? I mean come on...
Plot hole: Before giving his father's piece of string to his brother, Lars kept it in his suit's pocket, however in a scene in the factory, we see that Lars' suit gets entirely destroyed and yet later on in the film, he somehow has the string.
Answer: No, it's just an intelligent and precocious mouse.
LorgSkyegon