Blackened Gulf Shrimp In a Cast Iron Skillet 

How to blacken shrimp in a cast iron pan.
I recommend doing this outside if possible.
If you are cooking at the right temp there will be a lot of smoke, and the seasoning produces a smoke that will burn your eyes, kind of like low grade CS gas.
I use Paul Prudhommes Redfish Magic - it's my go to seasoning for blackening fish, shrimp, or even chicken.
You'll also need some stick butter - I go for the unsalted.
Then shrimp. For this cook I went with the big pink guys.
Get the shrimp seasoned liberally,
Get your cast iron super hot,
Throw some butter in and your first batch of shrimp.
Flip after maybe a minute and a half or so,
Add some butter, another minute and a half or so.
Pull them off.
Do your next batch.
Take the cast iron off the heat, add the rest of the butter and throw all the shrimp back in the cast iron and serve.
The shrimp will continue to cook at first until the cast iron starts cooling so it's not recommended to overcook during the first part of the cook.
Music -
Jackson F Smith // Cantina Rag
Shake That Little Foot // Pretty Little Dog
Dutilleul // Dark Room Full of Lonely People