How do you unlock the last play mat on toy story 3 the game?

To unlock the last play mat in Toy Story 3: The Game, you need to complete the game's challenges and collectibles. Specifically, you must earn all of the game's "Collectible" items and complete the storyline missions. Once you achieve this, the final play mat should become available for use in the Toy Box mode. Make sure to check the main menu for any updates or additional requirements if it doesn't unlock immediately.