The last of the 100 page issues, Shazam! 17 (March/April 1975) has a Marvel Family story by O'Neil and Schaffenberger. Oddly, the one new story is not any of the three featured on the cover.
The story centres on Allegro Scruff, a strange musician. At the top of the story a huge crime wave is going on, which Allegro brings to an end single handedly, using his music to make all the criminals march straight into a police station to give themselves up.
The city had promised Allegro a million dollars for doing this, not believing that he could. When they renege on their promise, Allegro vows revenge. It's all exactly like the Pied Piper legend. Allegro uses his music to call aliens to Earth, hoping they will cause a lot of trouble.
But that's not exactly what happens. Mary Marvel handles the first alien invasion, although all the beings want is to take away our pollution and keep it for themselves.
The next group of aliens , who Captain Marvel Jr deals with, steal a whole bunch of candy, but then wind up with cavities, and decide never to steal candy again.
It's only the third group of aliens that prove to be a problem, stealing the colour green. They also wind up kidnapping Mary Batson, unaware that she is Mary Marvel. Captain Marvel and Captain Marvel Jr make the aliens happy by giving them green tinted glasses, so everything will look green to them. The aliens are so happy they give Cap a million dollars worth of diamonds. Cap turns these over to Allegro, feeling he was owed the money the city wouldn't give him. But Allegro didn't want the million dollars, he just wanted to be recognized and appreciated.