Pinky Swear
Tom Riddle stepped back to study his handiwork. Not bad for a 17-year-old just out of school. Lucius was gritting his teeth in pain as he held out his left forearm, his sleeve rolled up and his fist clenched. Facing Tom was a tattoo of half a skull with half of a snake coming out of its mouth.
"Now, Lucius, before we proceed any further, you must answer a question. You will answer it truthfully, and if you give me a dishonest answer, I well have no choice nut to kill you."
"The question, my lord?" asked Lucius stiffly.
"Will you be loyal to me? We can't have traitors in our ranks." Tom paced around the room, studying the high painted ceilings, the tall windows with the painted curtains. It was a small room, the usual one for late-night talks.
"Y-y-yes, my lord."
"Lucius, you must make the most solemn oath a wizard can make. Or a Muggle, for that matter." Tom stopped pacing and stood facing Lucius, forcing him to meet his eyes.
Lucius gulped. "You mean the Unbreakable Vow, my lord?"
"No." Tom's eyes seemed to redden in the darkness. "I mean the Pinky Swear."
Lucius trembled, him arm held tight now in Tom's long fingers. "I-I haven't heard of that oath before, my lord. What must I do?"
"We shall link pinkies and shake them. If you break the oath, your pinky will become gangrenous and fall off." Tom smirked. "We all know what happens then."
Lucius's eyes were wide. "If my pinky falls off, my wand will cease to work! My powers... I'll be a Squib!"
"Exactly, Lucius. Do you swear?" Tom held out his long left pinky to Lucius.
" I swear, on my left pinky, that I will be loyal to you, Lord Voldemort, for the rest of my life."
There was a blinding flash of purple light. Both men's pinky fingernails glowed.
"I hope, for your sake, that you keep your promise, Lucius."
Tom Disapparated on the spot in a swirl of black cloak.
Lucius looked down at his left arm. He was branded for at least Voldemort's life, if not his own. The Dark Mark was complete.