IV wt tank destroyer was designed on the basis of IV tank in February 1944. At that time, the development of another tank destroyer with 128 mm pak44 artillery on the basis of tank IV was stopped and only existed on the blueprint.

This thing really exists

Weapon transporter 4 was developed in 1942. The initial design goal of this thing was to achieve a maximum speed of 17km / h, the turret could rotate 360 towers, and the 8mm gun shield could protect the members and intercept different main guns. The design was completed in 44 and was ready to put into production. However, the military didn't want to affect the production of No. 4 because of the war situation