Trung Cao bought a headlamp on Amazon.com, Inc.’s (defendants) website. The website identified a third party, Dream Light, as the seller of the headlamp. Under its fulfillment contract with Amazon, Dream Light set the price, provided the product description, and shipped the headlamp to Amazon’s warehouse. Amazon.com stored the headlamp, collected payment, deducted its fulfillment charge, boxed, and shipped the headlamp via UPS Ground. The agreement clarified that Amazon never held title to the headlamp unless Dream Light directed Amazon to dispose of it. Cao gave the headlamp to his friends, the Nguyens. The headlamp malfunctioned two weeks later, started a fire, and burned the Nguyens’ house, causing over $300,000 worth of damage. The Nguyens’ insurer, Erie Insurance Co., (plaintiff) paid the loss, then as subrogee sued Amazon for negligence, breach of warranty, and strict liability. The trial court granted summary judgment for Amazon, reasoning it could not be liable because it was not the “seller” of the headlamp. Erie appealed, arguing Amazon controlled significant aspects of the transaction, making it a seller like Home Depot or any other retailer who sells others’ products.