This is a prototype for the Imperial AT Hauler from Solo: A Star Wars Story. It's made from cardboard, paperboard, wood coffee stirrers, toothpicks, and clear plastic sheet. It's designed to be a Hasbro-style toy: It features a claw mechanism to grab, hold, and release Hasbro's Imperial AT-DT walker toy.
Like thewriteguy's 1:18 scale U-wing, he intends to release the templates and building plan photos for this AT Hauler for free!
To make your own, visit his tutorial: