The Tank in a box is, as it's name suggests, a small, grey tank, stored inside a cardboard box. The tank appears in the game Infiltrating the Airship, in which it is one of the many tools in the arsenal of the Toppat Clan.
The tank is stored in the Cargo Bay of the Airship. According to the box, it needs to be "handled with care". Several times during the game, the box containing the tank can be seen in the background whenever Henry Stickmin reaches the cargo bay.
The tank is only taken out of it's box once in the entire game. During the final choice screen for the Relentless Bounty Hunter ending, when Henry has captured the Toppat Leader in the cargo bay, the Tank is one of 2 options Henry can choose to leave the airship. When chosen, Henry takes the tank out of it's box (this happens offscreen), forces the Toppat leader inside, also gets in, and drives the tank out of the open bay doors. The tank plummets to the ground and crashes into the desert, but both Henry and the Toppat Leader survive this without any injuries, proving how extremely hard this tank is.
Henry hands the Toppat Leader over to the waiting military, and is pardonned for his crimes. During the end credits, Henry is seen driving the tank through the desert, happy to satisfy the government and celebrating his freedom
- This tank is in fact symbol of Newgrounds company and site, of which PuffballsUnited, the creator of the series is a member. The tank is piloted by Tankman, the mascot of Newgrounds. During the credits, Henry drives the tank exactly like the Tankman, which is the reference of the logo.