aiight guys ive done a full s5 t2 swap into my s5 na hook the starter up....and when i connected the battery terminal wires the negative started to spark and smoke up and melted the negative battery terminal....tell me what did i do wrong

 

Did you put the battery terminals on backwards?
Stupid question, but eh, you never know...

 

double check the connections on the back of your starter, you might have mixed them up

 

Check the positive post at the back of the starter. It has a 90 degree bend on it, make sure it is not touching the back of the starter. You have a short somewhere, something is grounding or the polarity is reversed.