Lower the bar down to the knees, as if you were doing a Romanian deadlift.
Explode into a vertical jump while holding the bar. Do not pull the bar. The arms stay straight.
Don't lower the bar too slowly. Just keep it under control. Be sure to finish the hip extension; make yourself "tall." Don't be surprised if you jump backward a bit when you get it right.
Thirteen interesting exercises you've probably never tried: new movements that'll break you out of your training rut and infuse some diversity into your workouts.