You’re an anaerobic microbe sunbathing on a Martian beach billions of years ago listening to the small waves hit the shoreline as you take in the perchlorates in the Martian regolith. This is because while Mars is warm and wet, it still lacks sufficient oxygen, so anaerobic life like yourself doesn’t need oxygen to survive. You’re chilling for several hours and eventually notice the water hasn’t touched you. You remember over-hearing some otherworldly fellows who briefly landed and discussed the landscape didn’t look well formed, so they left.