I remember my friend really wanted me to try Arch Deluxe back in HS senior year because he just learned how to make it (he worked there part time).
There were some weird ones along the way like the McDLT. It was just a burger with two parts in a clamshell package. The idea was that the cold side stayed cold so lettuce and tomato didn't get soggy being stored for several minutes on a warm patty. But that was back when McDonald's was still using styrofoam packaging. It got really weird around us because the city of Berkeley banned fast food styrofoam packaging at about the same time, and McDonald's started making special versions of the package made of cardboard. Of course they eventually stopped using styrofoam nationwide.
There aren't too many fast food chains still using styrofoam. Sonic is one. I've been to their location in Hayward and they don't allow it so it's just PET cups. And then CFA.