Spider-tracer

A spider-tracer is a fictional device featured in comic books published by Marvel Comics. It relates to the Spider-Man series of comic titles. A spider-tracer is a small device developed by Peter Parker as part of his crime-fighting arsenal. As Spider-Man, Peter can throw it or place it upon a moving target whereupon it automatically attached itself. From there, he can use his spider-sense to home in on the tracer, and by extension, track its movement.