Carriage, Motor, Amphibian, 105mm Howitzer, T87

[Subdeacon Joe]

This wild-looking thing is the T87, (full designation: Carriage, Motor, Amphibian, 105mm Howitzer, T87). It was an attempt to create an amphibious version of the M18 Hellcat tank destroyer. The running gear and lower hull are taken from the M18, but the upper hull is specially made to enable it to float. The turret was taken from the T88, and contains a gyro stabilised 105 mm gun. Despite these major modifications, the T87 could still reach 43 mph on land. It never entered production.
Another crazy weapon 

https://navalhistoria.com/the-pt-boat-elco-thunderbolt/