Recently, there have been an uprise of fake/counterfeit chargers, and charger adapters. Please use this website to check if your charger is fake.
The fake chargers can give VERY painful shocks. I highly suggest that after looking at this website, and you think your charger is fake, TAKE IT TO AN OFFICIAL APPLE STORE OR CALL APPLE.
Please do not flag this topic for being off topic. It is related to tech. I am also doing this for your own safety.
99% of the fake chargers can give a painful shock, so please try your best to contact Apple if yours is fake.
Have a good day!