Lake natron

 The extreme saltiness of the soda lake wouldn't turn you to stone like a glance from Medusa, but it would sting like hell if you had any cuts or breaks in the skin. Imagine what happens when you step into the salty ocean with a graze, it'd be like that but a lot worse.

When animals come in contact with the water of Lake Natron, calcium salts start accumulating in their body tissue, a process which is called calcification. As chances of survival are next to nothing, animals that fall into the lake start appearing as stones on the surface.