What is this bug? where the heck did it come from?

So i keep finding theese little spiders around and in my house. they are black and flat about a half an inch long. they look like little scorpions with out tails. they look mean as heck and im actually scared to kill them. lol im scared it might pick me up and throw me like in the commercial. but reallly wtf? we are in jersey sooooo not some sort of tropics