Make sure your pet is properly identified (microchip, collar and ID tag) in case she/he escapes through the open door while you're distracted with trick-or-treaters.
A microchip is a small, electronic chip enclosed in a glass cylinder that is about the same size as a grain of rice. The microchip itself does not have a battery—it is activated by a scanner that is passed over the area, and the radiowaves put out by the scanner activate the chip. The chip transmits the identification number to the scanner, which displays the number on the screen. The microchip itself is also called a transponder.