This is some knot I made up by accident while playing with rope.

Does anyone know what it is?

End product, slipped

Close up of knot, non-slipped

Make a loop

Make a loop with the working end, this will be about the size of the loop at the end.

Pass a bight of the working end through the initial loop

Bring the working end to the left (in this case) and go around the point where the initial loop crosses and through the bight.

Tightening's a little weird, but if you work at it you develop some techniques.

Well, it was weird for me, but maybe you're a pro.