Ariadne's Ball of Thread

Ariadne's Ball of Thread can be rolled out into a thin spectral thread to track where the person holding Ariadne's Ball of Thread has been. The thread’s length is infinite and can easily be tracked back, you can use its command word to remove all previously laid thread. Only the person holding Ariadne's Ball of Thread and creatures who can see invisibility are able to see the spectral thread.

The tread is spectral and cannot be burned, cut or destroyed, nor can it be used to tie something together or hold anything up. Anyone or anything trying to interact with the thread will move through it as if it wasn't there.