If you could place any object on the surface of Mars, purely to confuse NASA scientists, what would it be?

Interesting but what language would it be in? If it's English, I'm hoping NASA would be smart enough to conclude that one of their astronauts was just trolling lol.

I would probably put some sort of image engraving suggesting an ancient civilization. Maybe a bunch of monkeys worshipping something or diagrams of important scientific and mathematical concepts.

A WSO T shirt, obvs

If a single structure can count, then I would argue that a ziggurat or pyramid would be just about the best option. That would likely spark endless debate about the sophisticated society which created it and the religious or sacrificial or ceremonial purposes it would have had. They’d be looking for secret chambers and compartments and shooting sonar at it to see if there’s catacombs. All the poofy-haired talking heads on Ancient Aliens would be going ballistic.

Locate it on the polar caps or over a cave or in those volcanoes, and they will go hog wild.