Nagini

The witch Bertha Jorkins was on holiday in Albania when it mysteriously disappeared. Voldemort killed her and turned the giant pet snake, Nagini,a horcrux. The dark lord has a mental connection with your pet (evenHarry can enter the mind of the snake). She was killed by NevilleLongbottom in the Battle of Hogwarts, with the sword of Gryffindor.