The correct answer is ureter stone.
Urine passes from the kidney to the bladder via tubes known as ureters. A ureter stone refers to a mineral mass in the ureter that may or may not have arisen in the kidney and passed down into the ureter. A stone starts when mineral particles in the stagnated urine crystallize and produce a mass.
If the ureter stone is small, it will lead to no symptoms. If it is big enough to result in obstruction, it will inhibit the flow of urine and become extremely painful, followed by cramping in the region of kidneys and lower abdomen that may afterward spread to the groin.