The Shrunken Headmaster was once a stern, upright man, who ended up arousing the ire of a certain pupil. Unfortunately for him, she was a witch. Now, this same, formerly proud scholar is a shriveled, tiny body on a necklace. After several years of wearing the living talisman on her own neck, with a daily dose of taunting from the "schoolgirl", he was cast off. Fortunately for him, he was soon chanced upon by oblivious herokind, whereupon the man, more monster than human at this point, rediscovered his strict calling to education and discipline.
The headmaster will distinguish himself as a valuable charm to be grabbed up by the hero, a morbid trinket to be worn, with promises of otherworldly power. And beer. Once donned, the Shrunken Headmaster sets in motion his deadly prerogative: education. The heroes, are immediately put in perilous straits. With brains only provided with instructions for raising a beer mug, drinking, and remembering to breath, their cognitive faculties cannot process the immense weight of knowledge. The Headmaster, believes that this is a sign of progress, that the pain of discipline breeds fertile grounds for change and knowledge, and so, continues to berate the poor hero... with education.
If ever a scream in the cold dark night is heard, a shriek of crushing despair, a yell of "I don't understand"!... The Shrunken Headmaster is claiming the life of a simple dimwit.
The Shrunken Headmaster can be easily defeated with a little presence of mind. A precise slap to the chest where he hangs, a hearty crushing him flat against the bosom with with a silencing palm, will suffice. Grumbling, he will truly then become a compliant artifact. And hoisted off onto the nearest trader. Who are obviously smarter and won't wear it. Or maybe, the hero will keep the Headmaster as travel companion, because even they know it's less painful to face palm someone else.