Two’s company, three’s a congenital anomaly

It caused no negative effects (but no filtration superpowers either)
CT

A patient and his doctors got a surprise when an investigation into a suspected slipped disc unearthed an extra kidney.

The 38-year-old male patient underwent a CT for severe low back pain only to discover, unbeknownst to him, he was the proud owner of not two but three kidneys: a normal-appearing left kidney and two fused kidneys in his pelvis.