Preheat the oven to 250°F and position the racks in the upper and lower thirds of the oven.
Spread the animal crackers out over two large sheet pans.
While the oven is heating, in a small saucepan, melt the butter over medium heat. Add the sugar and shoyu and stir until the sugar is dissolved. Remove the pan from the heat and stir in the agave and oil. Pour the syrup over the animal crackers, then sprinkle on the furikake, using a silicone spatula or wooden spoon to stir the crackers until evenly coated.
Bake, stirring the animal crackers in each pan about every 15 minutes, until the crackers are golden and starting to brown around the edges, about 1 hour. Swap the sheet pans from top to bottom halfway through for even browning.
Let cool completely, stirring occasionally to keep the crackers from sticking together (they will look wet and soft when they come out of the oven, but will dry and harden as they cool). Store in an airtight container for up to 1 week.
