Witch's Beaver 

Witch's Beaver |'wich-əz 'bē-vər| - noun, vulgar slang :
The coldest thing in the known universe, measured only in Kelvin. Space itself is not even that cold.
(Even in Star Trek they never found anything this cold.)

RELATED TRIVIA:
• The White Witch was rumored by the satyrs to have held Her's in reserve as the last line of defense against Aslan.
• The flagpole in "A Christmas Story" was almost that cold.

ORIGIN early 20th cent.: I have schizophrenia and the voices I hear all the time and I came up with this one while reminiscing over a dream I had.

also see: Beaver, Witch's Tit, Absolute Zero

NASA TECH: "...And don't forget to seal your space suit before you go out there -- it's cold as witch's beaver out there."
ASTRONAUT: "Got it!"

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DECK OFFICER: Sir, Commander Skywalker hasn't come in through the south entrance. He might have forgotten to check in.
SOLO: Not likely. We'll have to go out on Tauntauns.
DECK OFFICER: Sir, it's cold as witch's beaver out there. Your Tauntaun'll freeze before you reach the first marker!
HAN: Then I'll see you in hell!

Witch's Beaver by Mrityunjaya February 19, 2013