I think it’s a large variation of a syringe needle that chips our pets, but aside from that monstrously large setup that isn’t even used on humans, no.

Closest thing I can think of is the capsule sized camera that can be swallowed to collect data as it travels through that long tube that connect mouth to anus. Even then, I’ve never seen that setup used on anyone.

You can't see them without a microscope, duhhh.

That's why they're called MICRO-chips.

In the bio hacking world, yea. There are reprogrammable RFID implants that you can get. They are rather large though and kind of suck when trying to use. Check out dangerousthings.com