Preheat your oven to 350°F (175°C).
Grease a 9x13 inch baking dish—or don’t, if you like to live dangerously.
In a big bowl, dump the cake mix and the entire can of pineapple with juice.
Mix until combined. No need to overthink it.
Pour the batter into the pan and smooth it out.
Bake for 25–30 minutes, or until it looks golden and your kitchen smells like vacation.
Let it cool a bit before slicing, unless you're okay with lava cake-style fingers.