why the fiends always wait 20 years to get their revenge?
couldn´t they kill their killers the next day? instead, they wait 20 years and go after teenagers that don´t even know what they parents did. its unfair.
shareThink of Patrick Swayze in "Ghost" - it takes time for a ghost to build up the "strength" to manipulate physical objects. Think of "The Sixth Sense" and "The Others" - sometimes dead people don't realize they're dead for a while.
Also, if you're kinda pissed off and blaming your castmates for accidentally hanging you, making them suffer their loss of *their* children would be uber revengeful.