TYB!
Was just reading this article, and verbalized "that's a bullet inside the head!" when I read this passage:
<In a simulation watched by AFP, the robot a metal cylinder just a few millimeters long, in the shape of a tiny bullet slowly follows a pre-programed trajectory through a gel-filled container, which emulates the density of the human brain.
<Once it nears a pouch filled with blue liquid,the robot is swiftly propelled like a rocket and pierces the sack with its pointed end, allowing liquid to flow out.
https://www.france24.com/en/live-news/20220413-california-start-up-sends-tiny-robots-on-voyage-into-brains
No matter how tumorous my brain becomes ("naht a two-more!"), I don't think I'll let one of these bullets zip around in my brain…