It was Temple of Doom that the PG-13 was actually created for due to the heart ripping scene, which was cut in some of the international versions.
Omg you're right. All these years I thought Raiders was the movie that started it all.

After you mentioned that I did some searching around, and technically Red Dawn and Dreamscale were the first films to get the PG13 rating, but Temple of Doom and Gremlins is reported to have caused all the fuss to begin with, to prompt the creation of PG13. Funny how when you think you know history, you don't sometimes.

Thanks for the tip!