Wind Lance

Wind lance was a massive weapon with a wide range used in the Third Age. It resembled a giant crossbow or ballista and was capable of firing Black Arrows, a series of big metal quarrels that were deadly even to the dragons. It was designed by the Dwarves of the Lonely Mountain and used by the Men of Dale and Lake-town. [1]

The Wind Lance is a weapon that first appears in Peter Jackson's The Hobbit trilogy.

The Wind Lance mounted on a tower is used by Lord Girion of Dale to fire Black Arrows at Smaug, the Dragon Dread. Only a portion of the beast's body is chopped off when the fire-drake tries to rain down fire upon the city. However, Girion is unlucky and gets killed before slaying Smaug with deadly arrows.

The Dwarves witness the wind lance on the top of a tower in Esgaroth as it is moved from Dale.

Smaug destroys the Wind Lance. Bard resorts to a makeshift wind lance using his son, Bain, as the Black Arrow and kills Smaug.

1. ^What became of the windlance at Lake Town? : TheHobbit - Reddit." 19 Apr. 2015