Packet Rat

A total Bad-Ass. The word is originally a nautical term for tough Irish men who sailed the north Atlantic. They were the best drinkers and singers. Not interested in anything fancy, they were talented sailors, and hardcore dudes.

In modern use, a Packet Rat doesn't need to have a direct connection to the sea, or a connection to Ireland, they would just be an immensely hardcore fellow.

A: That guy's a hardcore sunnuvuhbitch...
B: A Packet Rat, through and through.