In a lrg pot get milk and half and half hot. Whisk in gravy mix and let bubble to thicken. Remove from heat so it doesn't scorch.
In skillet melt half stick real unsalted butter.Add shrimp and a dash or two of creole seasoning, cook on med low, they cook fast so make sure you don't overcook. Add crawfish to shrimp and let cook just till warm.
Add butter,seasoning,corn to gravy and mix well.Pour skillet of seafood and liquid they cooked in,into gravy mix and stir well.Ready to eat when hot and bubbly!!