Ah yes, the E100 Krokodil, or how an urban legend gets its own life.
The Germans never made mention of any future plans involving the E100 chassis. Now because almost every German tank chassis had been used to build some assault gun or tank destroyer it was suggested that such a design would appear sooner or later.
And then somebody made a few purely speculative plans of what an E100-based design might look like and it acquired the name "Krokodil" The artwork was mistaken for German paper panzer plans and more artwork was made on that basis, upon which a Chinese company made a 1/35th scale model which made it practically official
But it never even existed as a paper panzer, napkin sketch or even as propaganda, because people found reference material that referred to itself.
Same thing with the alleged KV-VI
A nice little kitbash, but I've had people tell me with a straight face that it was actually built and there are some really convincing documents doing the tours on the internet that seem to confirm it is a genuine project, but have absolutely no basis in reality, not matter how crazy you like to think Stalin was
Even the original artist admits he was mistaken and thought it was genuine, of course now this image is sterling incontrovertible evidence that it is 100% genuine.
Same thing with this Soviet Kalinin K-7, the original was a fairly large and impressive machine, but when somebody had a little 3D fun it became a flying battleship.
link
Again you have several accredited forum "experts" who will tell you it was a 200% legit project, but "censored" because it was too advanced