There is a tool used in robotics that is essentially just a rod of metal with a sharp point.
It is fastened to the robot not for the purpose of manipulating, stabbing or poking holes, but solely so the user can move the robot to a certain point in space. The tip of the tool provides a sharp reference point, and the user can move the robot until that point is at the desired position.
The German word I heard most often is "Teachspitze" or "Teachdorn", which is a faux-English term meaning "teaching tip" or "teaching thorn".
What is this tool called? Is there a professional term for it?