Island Yo-yo

The Island Yo-yo is a yo-yo that was inexplicably handed down for generations by the people of Coralcola as a mythical weapon. It winds up in the hands of Mike Jones during StarTropics and serves as his main weapon throughout most of the game. It never runs out of ammo.

Using the weapon's long string, Mike can attack at a distance. Granted, almost every weapon in the game has more range than it does, but almost every weapon in the game has finite uses, so shut up.

The Island Yo-yo receives a couple "upgrades" (the Shooting Star and later the Super Nova) which improve its range and damage output. However, each one requires an increasingly large amount of health for Mike to use, and upon dropping below the necessary threshold, his upgraded yo-yo will revert back to its predecessor until his health is restored.

Just like quite a lot of things from the first game, the Island Yo-yo and its successors are nowhere to be seen in Zoda's Revenge: StarTropics II.

Trivia

 * The Island Yo-yo is renamed to the Island Star in the Virtual Console release of StarTropics, and stays that way on the NES Classic. This is almost certainly because "yo-yo" is a trademarked term in Canada.