During 2015, Hank Pym carried the Shrunken Tank to Pym Technologies Headquarters when he was invited by Darren Cross to see the unveiling of the Yellowjacket Suit. He presented the Tank, attached to its keychain, to security at the front of the Building.
Much later, at the beginning of the Infiltration into Pym Technologies Headquarters, Pym presented the tank again to security.
- "All the chaos in here! Multiple shots fired... and there's a tank."
- ―Jim Paxton[src]
Once Cross had shot Pym in the shoulder and escaped, and the charges of C4 that Scott Lang had planted were about to go off, Pym told Hope van Dyne that the Tank that was on his keychain was in fact a real tank from World War II. He returned the Tank to its original size, climbed aboard with van Dyne, blasted a hole in the side of Pym Technologies Headquarters and promptly drove out though the hole, returning the tank to its smaller size once they were free.
- The Shrunken Tank keychain has the number 153 on it, the same one that the tank shown in the footage that Darren Cross obtained about Ant-Man's missions during the Cold War.
- Pym Particles are said to only shrink the distance between atoms, but remain the same mass. However, when the tank is shrunk to the size of a keychain, it becomes very light, and can be carried around with ease.