What is this bug. I’m in northern cali
I think it’s a milkweed assassin bug. It’s a good guy 
I agree with @elheffe702
It’s apparently called an “assassin bug”. It’s a friendly; It only assassinates other bugs, but a defensive bite can be “excruciating” LOL here’s the link
I love predatory insects.
Not an insect if it has other than 6 legs. Maybe an arachnid? (like a spider?)