system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How tattoos work.

Basically, how do they get ink to permanently stain your skin? How does the ink stay in your skin even though your skin cells constantly keep shedding? How do they get the ink to get into the skin in the first place? Why is the removal of a tattoo so difficult?

Edit: Thanks for the replies. One more question: How does the needle and ink thing work? Basically, can you explain in a little more detail how the needle and the ink part of the process works?
gpt
basically, they use a big needle to put ink into the lower layer of your skin so it won't shed, and the ink particles are big enough that your body can't get rid of them, so they stay right there where they put them.