A whangdoodle would eat ten Oompa-Loompas for breakfast and come galloping back for a second helping.
-- Roald Dahl, Charlie and the Chocolate Factory, 1964
...he told her she was the most beautiful horse he'd ever seen but he wouldn't care if she were the ugliest whangdoodle in all creation, he'd still love her...
-- Robert Coover, Ghost Town, 1998
Origin:
Whangdoodle is a neologism from the 1850s. It is most likely a nonsense formation.