La Casa (lit: The House) is the name given to a collection of mostly unrelated horror films which were retitled and marketed in Italy as one single series.
When first released in 1981, the Sam Raimi-directed horror film The Evil Dead was distributed in Italy under the title La Casa, where it was a box office success.
The 1987 sequel Evil Dead II was thus distributed under the similar title La Casa 2, and also did well in the Italian box office.
Attempting to capitalize on the successes of the Evil Dead films, Italian filmmaker Joe D'Amato produced an unofficial sequel titled La Casa 3 (later released in English-speaking countries as Ghosthouse).
To add further confusion to the matter, The Horror Show was marketed as a sequel to House II in other non-US markets, using the title House III: The Horror Show, as had been the original intention for the US release during production.