Spam is a "delicacy" which is questionable for me and this dish is found from Hawaii to Okinawa.
Spam is a processed meat product packed in a can and as such was great part of military rations during the WWII. It tastes very salty and not really of meat but of MSG.
It is not available in supermarkets here in Germany, which is a blessing. I had some during one of my many stays in the US and I wont eat it again.
But here in Germany we have a very tasty alternative. It is called Fleischkäse or Leberkäse. It is seasoned pork and beef meat, which is grounded into a very fine paste, shaped into a loaf and put in a loaftin and baked in the oven. Cooled down, it is served as cold cuts on bread, or thicker slices can be baked in a pan in some butter. Many love them on a fresh roll from the bakery as a lunch snack.
This is sold in a couple of different flavours (like onion or pizza).
I saw Musubi been made on YT by Emmymadeinjapan and though what a quick snack for the evening.