Friendship knot loop
Friendship knot loop is a knot to tie a secure and stable loop at the end of a rope.
The slipped version where the last move is done with a bight of the end, rather than with the end itself, is one that can be tightened flat, slid, locked, and then untied quickly with an exploding pop. If not tightened flat, this Slipped friendship knot loop collapses into a cube and will neither slide nor pop.