NiseTwinBee is Dr. Warumon's personal android. He greatly resembles TwinBee, although he is much larger than him and features a black color-scheme along with red turbines, stabilizer and windscreen. He appears in the very last square of the game's map and acts as Rainbow Bell Adventures' last boss.
At the beginning of the encounter, Dr. Warumon, initially riding a levitating platform, enters NiseTwinBee's body and then the battle starts. NiseTwinBee has several attacks at his disposal, each announced by adopting a different color-scheme:
- Black / Red: Standard color scheme. He uses this form to reposition himself across the room at great speed to prepare his next attack, bumping into the player if they get in his way.
- Light Blue / Yellow: TwinBee's color-scheme. NiseTwinBee jumps straight up and out of the screen, and comes back down a moment later attempting to land on the player. He then starts hurling giant bombs in an arcing pattern.
- Pink / Blue: WinBee's color-scheme. NiseTwinBee launches himself straightforward across the room at great speed, covering the entire ground level. If he hits a wall, he will keep changing his trajectory to the opposite direction until the attack ends.
- Green / Blue: GwinBee's color-scheme. NiseTwinBee starts swinging his arm and then unleashes a powerful energy blast straightforward.
At the end of the battle, all four androids: TwinBee, WinBee, GwinBee, and a badly damaged NiseTwinBee, attempt to escape Warumon's soon-to-explode laboratory. After exchanging a few words, mocks and threats, the three heroes manage to get out while NiseTwinBee, with Dr. Warumon inside, is engulfed by the explosion.