NASA's Perseverance Mars Rover

For God's sake, stop it with the conspiracy theories. Trace Gas Orbiter would absolutely not miss the, well, methane emission, from a single baby cow, let alone an adult specimen worthy of being prepared as wagyu. Everyone knows that a Japanese master chef would quit (or worse...) before disgracing himself thus. He would never abandon a thickly-marbled specimen on a great big windy crater rim like this.

This is Mars. If you want your vulgar gyudon, there's plenty of that on the mad blue planet next door. Martian wagyu should be part of the finest sukiyaki, to be eaten in formal dress, in deeply contemplative silence.

... I should add - if you can get a sample of this rock for us, we'll even let you eat part of it. It might be a bit salty, but you can be pretty sure Martian beef is nitrate-free...