Stupid dog!

Eustace always refers to Courage as a "stupid dog" even though he himself isn't aware of the dangers that goes around in Nowhere, and Courage is the one who usually has to save him and Muriel. At least four antagonists have borrowed Eustace's catchphrase of calling Courage a "stupid dog" (the characters being King Buffo from "Feast of the Bullfrogs", Jeeves Weevil from "Evil Weevil", Dr. Zalost from "The Tower of Dr. Zalost" (not shown here) and Muriel in "Car Broke, Phone Yes". Even after his original actor, Lionel Wilson retired and Arthur Anderson took over, it still uses the old stock sounds for Eustace.

Example of:
Character Catchphrase