Are you trying to find our inner psycho? I would kidnap a blademaster and feed him claws (through his mouth ofc).
At first: the victim has to be a bad person, or someone with bad habits, so lets take Karune for spreading false news.
Telling ios something we do with our tongues, so that would be the body part.
Then a way of trapping him and a way to get out. What about giving him a big fucking tongue piercing and a timebomb. The piercing is the key to get out. He has to rip out his tongue and gtfo before bomb goes off.
Is that a solid idea?