I would have thought it was a joke if I hadn't stumbled across this peak while looking at some maps. If you have any idea, you should tell us how the name came about - possibly more interesting than climbing it!
The origins aren't nearly as colorful as the name would suggest. According to "California Place Names: The Origin and Etymology of Current Geographical Names" by Erwin Gustav Gudde, Butt Mountain, creek, valley, and reservoir were all named after a miner in Plumas County named Horace Butts.
"After the first glass, you see things as you wish they were. After the second, you see things as they are not. Finally, you see things as they really are, which is the most horrible thing in the world."
--Oscar Wilde on Absinthe