When trying to hook up negative cable there was a big spark

Hello, I am Danny.

Interesting! Well let me ask you first. Was any type of electrical work done? (Aftermarket stereo or components) That would possibly be installed incorrectly? Also, are you sure that the cable was the negative and not positive. It can happen sometimes if they look the same. Hope this helps and feel free to ask any questions if needed. Thanks for using 2CarPros.
Danny-