Admiral Grimmitz is a character from DuckTales. He is the Navy commander on the aircraft carrier that Donald is an enlisted sailor on. He always gets annoyed at Donald's accident-proned stunts, and likes to play with military equipment that makes things "go ka-blooey."
He was voiced by Peter Cullen, and the voice was based on that of John Wayne (much like how he did so with Optimus Prime). His name is based on United States Navy Admiral Chester Nimitz, who commanded American naval forces in the Pacific during World War II.