1. Grease a bundt pan or tube pan lightly with butter or nonstick spray and set it aside.

2. Place the popped popcorn in a very large mixing bowl and remove any unpopped kernels.

3. In a large pot over low heat, melt the butter completely.

4. Add the mini marshmallows and stir until fully melted and smooth.

5. Stir in the vanilla extract and salt until evenly combined.

6. Pour the marshmallow mixture over the popcorn and toss gently until the popcorn is well coated.

7. Fold in the candy-coated chocolates, chopped gumdrops, and sprinkles while the mixture is still warm.

8. Transfer the mixture into the prepared pan and press it in gently without packing it too tightly.

9. Let the cake sit at room temperature for 30 to 60 minutes, or until firm enough to hold its shape.

10. Invert onto a serving plate, slice, and serve.