What did George Lucas demand Mel Brooks concede to in making Spaceballs?

George Lucas demanded that Mel Brooks concede to a few specific conditions when making "Spaceballs," primarily concerning the use of certain elements from the "Star Wars" franchise. This included ensuring that the film did not directly parody or infringe on specific character designs and visual effects. Additionally, Lucas requested that Brooks not use the term "lightsaber" in the film, which Brooks complied with, instead using the term "Schwartz Ring" for the parody version.