Lark's Loop
Double Lark's Loop
A memorable end loop that can be tied around or through an object.  It appears more secure than a bowline in slippery rope and is jam-proof. 

When the knot is loose, you can adjust the loop size by working the standing part.  When you're done adjusting the loop size, pull the leg of the loop belonging to the lark's head structure and the standing part to set firmly.  The same procedure applies for the loop shown below.
Nearly as easy to tie as the Single Lark's Loop, but has an added measure of security for low-friction rope under more demanding conditions.  A Water Bowline or a Zeppelin Loop would probably be a better choice for slippery rope where the loop's security is put to the test with repeated flogging.

Adjust and tighten this loop with the same procedure described for the regular Lark's Loop.
Click to zoom in
Click to zoom in