From Dragon Ball Encyclopedia, the ''Dragon Ball'' wiki
Tapion's Sword is an enchanted sword that Tapion owns.
During the war between Hirudegarn and the Konatsians, Tapion and his young brother, Minotia, used their special Ocarinas to hold Hirudegarn at bay. Given this opportunity, a Konatsian Wizard brandished the enchanted sword and used it to slice Hirudegarn in half.
Under Trunks' possession
Main article: Future Trunks' Sword
After Hirudegarn's defeat, Tapion gave Trunks his sword and stated that it had always been meant for him (sort of referencing to the fact that Trunks' alternate timeline counterpart, Future Trunks Briefs, was almost always seen with his sword until it was destroyed by Android 18, and was then never seen again in the manga or anime with the exception of films. It was destroyed once again in Dragon Ball Z: Super Android 13! when Trunks tried to hit Android 13 with it, causing it to shatter into pieces. It was seen again in Dragon Ball Z: Bojack Unbound when Vegeta threw it to Trunks when Trunks was under the Galaxy Soldiers' Psychic Power. The sword was also seen during the opening credits of Dragon Ball GT.
This event has become a common misconception among fans, with many regarding the origin of Future Trunks' Sword the same as the sword given to the main timeline Trunks. The sword does, however, look exactly like Future Trunks' own blade, but is assumed to have been a mistake on Toei Animation's part. This may be why Trunks has a sword in Dragon Ball GT, but this cannot be the origin of Future Trunks' Sword due to the fact Future Trunks comes from a timeline where the Z Warriors are dead and the Androids reigned supreme. Not to mention Future Trunks apparently obtained his sword after Future Gohan's death, while Trunks got it as a child. Although it is also possible that Tapion appeared in Future Trunks' timeline and gave him the sword with Trunks doing what he was unable to do in the film in killing Tapion to destroy Hirudegarn. Another reason as to why it cannot be given to Trunks by Tapion is that, to open the music box, they would have to use the Dragon Balls, and at this time the Dragon Balls did not exist on Earth. Another possibility is that in his timeline, Hirudegarn was less powerful of an opponent. While too much for Tapion to handle on his own, Trunks could have managed to destroy him and therefore received the sword in thanks.
It is stated in Dragon Ball: Raging Blast that Tapion did give his sword to Future Trunks. This is the first official claim and the canonicity is debatable. It should also be noted that at the end of Wrath of the Dragon, the entire end credits is accompanied by scenes of Future Trunks using his sword.