what happens if snatch a drone carrying hundreds of thousands of dollars?

Run.

If the owner finds you… like if they have a camera recording and the GPS location… you might get some free bullets on top of it.

Spain has some relatively strict gun control. That doesn’t mean someone controlling the smuggling of millions of € in drugs, can’t pay a few grand for some of his “acquaintances” to fly all the way over, get his property back “by whatever means”, and fly back the next day.