Dug: My master made me this collar. He is a good and smart master and he made me this collar so that I can talk. Squirrel!.My master is good and smart.
Carl: It's not possible!
Dug: It is, because my master is smart.
When the house first becomes detaches from its foundation and becomes airborne, Russell is nowhere to be seen, although every angle of the house is shown, including underneath, the front porch and the back porch. He knocks on the door and tells Carl he chased a "snipe" under the porch - but he cannot be seen after liftoff and prior to knocking. The same thing happens near the end, when Dug claims to have hidden under the porch.
Jordan Nagai, who eventually got the part of Russell, showed up to an audition with his brother, who was actually the one auditioning. However, the director realized Nagai behaved and spoke non-stop like Russell and chose him for the part. A similar situation happened with the casting of Short Round for Indiana Jones and the Temple of Doom, whereby Jonathan Ke Quan was cast when it was actually his brother auditioning for the part.