How do you get Bigfoot to take the hat in Riddle Transfer the game?

In Riddle Transfer, to get Bigfoot to take the hat, you need to first obtain the "Bigfoot Hat" item. You can find this hat by completing specific tasks in the game. Once you have the hat, approach Bigfoot and use the hat on him to trigger the interaction, allowing him to take it. This will progress the storyline and complete that part of the game.