|Index||76 (N), 77 (W), 78 (S), 79 (E)|
A tank is a monster that continues moving in a straight line until it hits an obstacle, after which it stops and will not move again, even if the obstacle were to move, until a blue button is pressed. When hit, all tanks in the monster list that are voluntarily moving reverse direction and the same principles then apply. As with most monsters, all destructive obstacles will cause death to the tank, and like pink balls, they can switch polarity by landing on ice or force floors pointed in a perpendicular direction.
The tank is one of the most intricately programmed monsters in Chip's Challenge, alongside the teeth, due to its numerous rules of turning and the two glitches which can occur exclusively to the tank. For example, the Tank Top Glitch occurs if a tank hits a blue button after turning as a result of sliding on a single ice or force floor. Tanks sliding when a button is hit will not reverse since they are not voluntarily moving, and tanks on clone machines will only reverse as a result of the Frankenstein Glitch.
A closely related property of tanks is when they begin a level on a trap: when their brown button is hit and the released tank cannot legally move in its pointed direction, it will be free from the trap even after the button is released. When reversed, the tank will move. In this manner, it can escape the Concussion Rule since it can turn around without hitting a wall.
When a button is pushed, there are specific rules which determine when the tank actually begins to start moving in the opposite direction. The tank will either move on the same turn as the button press, or turn 90 degrees during this turn and then start moving backwards, on the next turn instead.
- All tanks already in motion when a blue button is pushed reverse on the same move.
- All tanks reversed on the first turn of a level wait .
- If Chip or a block touches a blue button and the tank is stationary, it will wait  unless Chip waited [1/2] before touching the button, in which case it will not wait.
- If a monster touches a blue button, all stationary tanks ahead of the touching monster in the monster order wait, and all stationary tanks behind will not. By inference, if a tank hits the button, that specific tank will always wait, but any tanks after it in the monster order will still turn immediately.
Use in play
Knowledge of this programming may be from useful to necessary, particularly when other monsters interact with tanks. Whether a tank will block a monster or let it through is often an exact science. An example is the following:
Assuming the pink ball is ahead of the tank in the monster order, it will move first. The tank is thereby blocked, and stalls where it is as the ball plays 2U 2D and then 3U 2D continuously until Chip decides to touch the blue button. This causes the tank to reverse itself onto the force floor and charge west. Assuming Chip does not use a [1/2] wait, these are the possible results:
- If the pink ball is standing at [1, 3] or moving north on [1, 2], it will stall the tank again.
- If the ball is at [1, 1], the tank will squeeze under the ball as it plays U or D and explode the bomb.
- If the ball is on [1, 2] moving south, the tank will explode the bomb.
- The first tanks in Chip's Challenge were placed in Lesson 4, to the left side.
- The tank clone machine is unusually rare in Chip’s Challenge. Only eight levels in all three levelsets have tank clone machines: Monster Lab, Catacombs, Hmmm!, Monster Factory, How to Get Around in Venice, Color Wheel, You Can't Teach an Old Frog New Tricks and Recurring Dream.