The Fuhgettaboutit lock

Millner Built Schwinn SS secured by The Fuhgettaboutit lock, like a gym in a sleeve at 15 lbs!

The Fuhgettaboutit lock. Article from Dirt Rag. 

This is the Dutch version of the "Fuhgettaboutit" lock! Details here. 

Bike Man Dan describes how to make a saddle lock here.