Do We have This one? Up for Grabs.
A weapon that extends far beyond the range that makes sense in reality. This is used a lot in anime and manga. The Trope Codifier in ancient literature would be Goku and his magical extending staff.
Anime and Manga examples:
Gin Ichimaru from Bleach. His sword extends to ridiculous proportions.
Goku from Dragon Ball. In the first part, like his namesake, he wields an extending staff.
Orochimaru's sword from Naruto also extends to extreme lengths.