mandelbug definition: Noun (plural mandelbugs) 1. (computing) A software bug whose behaviour appears to be chaotic. ...
The 1st Texas Infantry lost 82 percent of its menduring the Battle of Antietam, the highest casualty rate for any Confederate regiment in one battle of the Civil War.
I believe the original poster may have mis-remembered the TV documentary statement. I've often heard/read it claimed that the American Civil War was the bloodiest war in U.S. history, but I've never seen it claimed that it was the bloodiest civil war (ever) in history. However, even the claim that it's the bloodiest war in U.S. history is debatable. The figures usually quoted for American Civil War casualties are a sum of U.S. and C.S. casualties. By that type of measure (U.S. + enemy casualties) quite a few wars in which the U.S. has since participated were bloodier.