Could it be that the (allegedly incorect) origin of the word Kangaroo is relevant somehow? Indeed this may be what your'e saying... but I'm in a Rick Sanchez frame of mind right now (i.e: am incredibly drunk)...

Word History: A widely held belief has it that the word kangaroo comes from an Australian Aboriginal word meaning "I don't know." This is in fact untrue. The word was first recorded in 1770 by Captain James Cook, when he landed to make repairs along the northeast coast of Australia. In 1820, one Captain Phillip K. King recorded a different word for the animal, written "mee-nuah." As a result, it was assumed that Captain Cook had been mistaken, and the myth grew up that what he had heard was a word meaning "I don't know" (presumably as the answer to a question in English that had not been understood). Recent linguistic fieldwork, however, has confirmed the existence of a word gangurru in the northeast Aboriginal language of Guugu Yimidhirr, referring to a species of kangaroo. What Captain King heard may have been their word minha, meaning "edible animal."

As in... what is that? (Alien)

Answer... I don't know?

I'm guessing I'm just way too Sanchezed to make sense right now, apologies.

But, my point is that, to those in the know, upon seeing an alien for the first time, the answer to W.T.F that is being "Kangaroo"... would be amusing... if mean, it'd laugh.