Tiny objects have been found in humans. How did they get there? It is common for small objects to be stuck on skin and eventually get under the skin and can then move around the body. However, objects have been found in the brain which is an odd place for small grains to get to.
The tiny objects are just a few millimeters long and are nearly always magnetic iron from meteorites. People who have considered that they have been abducted by aliens and then had x-rays have discovered these implants. Were they possibly inserted by aliens?