While characters making guest appearances in other comic strips is not an unusual occurrence (Dan Piraro's Bizarro and Stephan Pastis' Pearls Before Swine do it often), this was the most ambitious in scale.
On April 1, 2005, Stephan Pastis of Pearls Before Swine, Bill Amend of FoxTrot, and Darby Conley of Get Fuzzy all ran the same comic dialogue in their respective strips, but with their own core characters saying the lines.