A derogatory nickname for any corporation or other entity that abuses IP laws to take down and remove any and all derivative works without regard to fair use laws. They're notorious for constantly issuing cease and desist letters and DMCA takedown requests to fan-works that in no way affect their bottom line.
Person 1: "Ugh, Nintendo's taking down fuckin' GMod stuff now!?"
Person 2: "Nintendo's an IP tyrant... What did you expect?"