The 44M Tas Rohamlöveg (Rohamlöveg meaning "Assault Gun") is a Hungarian tank destroyer design of World War II, based on the chassis of the 44M Tas heavy tank which was made up by mistake by the Hungarian historian Pál Korbuly. During his research in the 1980s on the 44M Tas heavy tank he found sources mentioning that components for two chassis of the 44M Tas were made and he jumped to the conclusion that the second hull was for a tank destroyer based on the hull of the 44M Tas design. Due to the very limited information on the 44M Tas project at the time this spread as fact fairly quickly. It was first later in the 2000s that more information was found which explained that the components made where for a second 44M Tas prototype and not for some tank destroyer variant. There is no direct evidence of the project. The assumption was made by the son (Pál Korbuly) of the lead developer (János Korbuly) for of the manufacturer (Weiss Manfréd) in the late 80's. The base of the theory was the 2 prototype suspensions of the Tas, jumping to the conclusion that the second one was for a TD. This was later debunked, as army officials actually ordered two full prototypes of the Tas Pál Korbuly in his research seems to have hinted that there was there was at least some idea based around making a tank destroyer on the 44M Tas chassis but no surviving documentation of this exists and if the idea actually existed it most likely stayed just as an idea and never went anywhere.
Hungary had experimented and made self propelled guns and tank destroyers previously so it's not too unlikely that something like the 44M Tas Rohamlöveg would have been made eventually if the 44M Tas project got to a more advanced stage.