The Frankenstein Glitch is a glitch exclusive the MS ruleset of Chip's Challenge, which allows tanks on clone machines to reverse direction. It is not required to solve any official levels or even to get any bold times, but it has been used in a few custom levels.
The cloning of monsters is handled by the game in several steps. When the clone button is pressed, if the tile in front of the clone machine is open, the stationary monster on top of the clone machine is added at the end of the monster list. The monster would then move off the clone machine, and a stationary replacement would then be generated in its place. If the clone machine is blocked when the button is pressed, the monster is never added to the monster list.
However, since the newly-cloned monster is last in the monster list, it is possible for the clone machine to have become blocked when it is time for the newly cloned monster to move. This results in the monster remaining on top of the clone machine; however, should the tile in front of the clone machine ever become open again, the monster will be able to move off the clone machine, and the cloning process is completed. This phenomenon is a possible relative of the Concussion Rule, with clone machines instead of traps.
Tank buttons affect all tanks on the monster list, including tanks produced under the circumstances described above. Therefore, when the tank button is pressed, the tank on top of the clone machine would turn 180° like any other tank would. If the clone machine is open on the other side, the tank will then exit, and the replacement monster is created facing the same direction as the one that just exited. If the clone machine is blocked in the other direction too, the tank will still flip, but will remain on top of the clone machine.
Early versions of Tile World did not emulate the glitch correctly, but versions 1.3 and above have patched the glitch in.
The Frankenstein Glitch is not required to solve any official levels, but it can still be observed in a few levels such as Monster Lab. In other levels, such as Catacombs, it is possible to produce living tanks on top of clone machines, but the absence of tank buttons prevents them from ever being freed. There are also several custom levels that require the glitch to be solved, notably David Stolp's level ode to a cloned tank, pointed the wrong way.
In the example above, the pink ball is moving down and will press all three buttons. It will first press the clone button; since the clone machine is open, the tank on top of it will be added to the monster list. The pink ball will then press the toggle button, blocking the clone machine. It should now be the tank's turn to move, but it is unable to. However, the pink ball then presses the tank button, which causes the tank to rotate 180° and point upwards. Because the clone machine is open in this direction, the tank is able to move off and a new immobile tank can be created in its place; the tank was moving north when it left the clone machine, and therefore the tank on the clone machine will now point north.
If the tank button had been replaced with another toggle button, the tank would have continued down instead.