granny knot 
noun
A reef knot with the ends crossed the wrong way and therefore liable to slip.The procedure doesn't distinguish, for example, between the granny knot and the square knot even though it is impossible to deform one into the other....
- It was a process a bit like tying a granny knot: twisting one edge of the sausage rope into a loop, then threading the other end through, looping it, and twisting again.
- Blow the balloon up to a normal size and knot the end tight with a granny knot.