It only happened in *_Goblet of Fire_* because of Harry's and Voldemort's wands sharing the same core. Harry's wand was able to connect to Voldemort's and bring out the most notable spirits that he (or in the case of Cedric, Pettigrew) killed over the last 13 years at that point. It also partially explains why Harry's wand could handle using the Cruciatus Curse in *_Order of the Phoenix_* and _Sectumsempra_ in *_Half-Blood Prince_* rather decently, along with sensing Voldemort's presence at the beginning of *_Deathly Hallows: Part 1_* during the chase to the Burrow. As far as the other times, *_Goblet of Fire_* also showed that in its own unique way, the _Expelliarmus_ charm is the only spell that can block the Killing Curse.