First step DO NOT USE.
Send it to Samsung to have it looked at. Explain as much as you can when you submit a ticket. More than likely it's just going to be you purchasing a new one. For your safety please do that.
I just woke up and had my phone on my bed next to me charging and mine started to spark and flame so I pulled it out of my phone and wall.. I am just happy this didn't happen while I was sleeping. This can start fires and be very dangerous. .. what causes these chargers to spark??