I can already see plot holes, but this is the best I could come up with. I was going to suggest that the 3 eyed alien toys are real aliens. They were sent to earth to observe human behaviour from birth to adulthood and have the ability to shapeshift into other toy forms. read more
The Toys that appear within the Toy Story universe are able to animate to life. Toys have a unique biology, psychology and culture compared to humans. The Toys that appear within the Toy Story universe are able to animate to life. read more