World’s Finest 243 (Feb. 77) is the last issue in this format, and has Robin guest star alongside Superman and Batman. He proves mildly more useful than he did as a regular member of the team in this story by Haney, Swan and Al Milgrom.
The story has to do with the moving of ancient monuments in order to build a dam but preserve them. Although the ones shown resemble the heads from Easter Island, the story of the dam draws from the moving of the Temples of Abu Simbel and the construction of the Aswan Dam.
Aliens are given the credit for building them, and coming to retrieve them in order to stabilize their new world. Formerly of Earth, they left when the atmosphere became toxic. Robin gets taken hostage, but uses his time profitably, figuring out that the aliens would now be able to breathe on Earth.
So a happy ending is found for all, although its a little odd that Superman and Batman think the aliens will live safely and happy on Earth.