The Slytherin Sisters, Alex and Alexis were well known troublemakers at Hogwarts.  Snape and other faculty had to be on constant alert for there was no telling what mischief the sisters would get into next.  Alex wears an amulet that is able to charm others by just looking at it, while Alexis wears a ring that freezes anyone who touches it (except the wearer).  The sisters were accused (but never proven guilty) of vandalism of the Fat Lady’s painting, as well as a large explosion in Snape’s potions class which resulted in t he evacuation of the whole school and two Ravenclaw students smelling like eggs for months; Even the headmaster was not spared when dragon-fire hot sauce was slipped in Dumbledore’s coffee which caused most of his hair to become singed.  Both were gifted witches academically and by ability, however they caused Dumbledore much grief at the time they attended Hogwarts.

R.I.P.  Alan Rickman 2016