living end, the
The utmost in any situation, something quite extraordinary, as in When he threw the stereo out the window—well, that was the living end! or That performance was the living end. [Colloquial; late 1930s]
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.