When you try to interfere with another person's Puppet Strings, roll +weird. On a hit, choose options. On a 10+, choose 3.
On a 79, choose 2 and youre acting under fire from your patients brain, or choose 1 and all's good on your end:
the puppet survives, whole and unharmed
you get a line on the puppet-master and can track the string
you can stop the puppet-master from using the string
you suffer little harm
On a miss: first, you dont affect the string. Second, youve opened both your brain and the puppet's to the worlds psychic maelstrom, without protection or preparation. For you, and for your subject if your subject is a fellow players character, treat it as though you've missed the roll to open your brain. For subject belonging to the MC, their experience and fate are up to the MC.