
Mondegreen was not in my vocabulary (neither active, nor passive), so I've just checked some dictionaries and wanted to share its etymology
American Heritage
After (Lady) Mondegreen, a misinterpretation of the line (hae laid) him on the green, from the song “The Bonny Earl of Murray”.
Dictionary.com
Origin: 1954; coined by Sylvia Wright, U.S. writer, from the line laid him on the green, interpreted as Lady Mondegreen, in a Scottish ballad
Funny!

By the way, I didn't get this mondegreen:
Grammar Geek "Scuse me, while I kiss this guy"
What does it stand for? Thanks!