I’m prepared to be crucified for this, but I’ll give you a real answer. The Japanese “Winners Face” trophy cards are probably the rarest in every sense of the word.
I have a burned Gold star Mewtwo which survived a fire at my friend’s high- school home. Since fossil Magmar is a far more common card, and spilled BBQ sauce is a far more likely event than a house fire, it’s far more likely (less rare) for the combination of things to create my Gold Star Mewtwo would be far less likely (more rare) than to create your Magmar, Even though we don’t know that there are more copies.