Preheat the oven to 255 degrees F (124 degrees C).

Combine corn snacks, cheese crackers, popcorn, and pretzel sticks in a large roasting pan.

Bring brown sugar, corn syrup, butter, and salt to a boil in a medium saucepan over medium heat, stirring occasionally. Cook, stirring frequently, for 5 minutes. Remove from heat; stir in vanilla extract and baking soda. Pour the syrup over the snack mixture in the roasting pan; stir to coat.

Bake in the preheated oven for 1 hour, stirring to coat every 15 minutes.

Line a countertop with waxed paper. Spread snack mix into a single layer on top.

Place candy coating in a microwave-safe bowl and heat for 1 minute. Stir until smooth and place a dot of the melted candy on the back of a candy eyeball; attach to a corn snack. Repeat with remaining eyeballs.

Transfer snack mix to a large bowl. Stir in candy corn and peanut butter candy pieces.