Twin Hammer (ツインハンマー) is the Sub Boss encountered in Act 1 of Launch Base Zone. According to the character used by the player, two versions of this boss exist. Sonic and/or Tails have to fight a single instance of it, while Knuckles has to fight two, in another boss arena which will eventually lead to Knuckles' own path in Act 2.
Each instance of this boss floats in mid-air seeking for the player but keeping a certain distance from him, and is equipped with two spiked small balls, attached to its main body with a short chain-like connector. Said balls will be spun around by the boss, leaving some window to attack its main body. After three hits, one of the spiked balls is removed; after three more hits, the boss is defeated. Each time it's hit, it quickly moves up, which makes it impossible to use very long combos, even when playing as Hyper Sonic, and is actually frustrating when playing as Super Tails because of his 4 super flickies.