The Experiment/Gameplay

The Experiment is an artificial being created by Dr. Finkelstein, and is found in Kingdom Hearts II. It is one of the bosses at Halloween Town. Like the Guard Armor, the individual pieces of the Experiment's body are able to act on their own.

Although it is not technically a Heartless, the information given when the game is paused says to defeat Doctor Finkelstein's experimental Heartless. The Experiment, along with the Hostile Program, are the only boss characters in the Kingdom Hearts games who are not Disney characters, Final Fantasy characters, major original characters of the Kingdom Hearts setting, Heartless, Unversed, or Nobodies. Rather, the Experiment is a character within the Nightmare Before Christmas setting who did not appear in the movie, but clearly shares the distinctive art style of that film's characters. It is identified in Jiminy's Journal with a red background on its panel, symbolizing its role as an antagonist.

Strategy
The Experiment acts similarly to Guard Armor and Opposite Armor in battle. While at first being one large enemy with a variety of attacks, it eventually separates into smaller enemies composed of different combinations of its parts. Little damage can be done to the parts individually, but the use of carefully timed Reaction Commands can bring it back together, and it can be defeated in this way.

The Experiment has a large variety of items from The Nightmare Before Christmas, such as its left arm being the vent Lock, Shock, and Barrel used to send bugs to Oogie Boogie and its right arm being the device Oogie was about to torture Santa Claus with. In conjunction with these, it uses combinations of laser and shockwave attacks against Sora, and uses wind-based attacks to knock back Sora, keep him airborne, or prevent him from attacking. The Kickspring Reaction Command counters the Experiment's attacks and is the only way to bring it back together to defeat it.