The Tongue-Tying Curse (Mimblewimble), also known as the Tongue-Tying Spell, binds the target's tongue to keep him or her from talking about a specific subject. This feature also allows one to prevent the victim from incanting, and hence—like the Silencing Charm—it is useful when duelling (though could be overcome with more advanced magic). It is covered in the book Curses and Counter-Curses.