National Girlfriend Day, on the street you see a couple giving you a bouquet, bracelet, chocolates, and so on. You go home, when you get to the front door and open it... it turns out there's already Xanders, he gives you a small gift box, then he tells you to go inside the house, he closes the door behind him, you open the box there is a strange thing based on iron

"What's this?"

He smiled and said "It's a necklace(as well as a chain for animals)"

He puts on her necklace and locks the key in the heart on the necklace

"Won't it pinch your skin??" He makes sure not to hurt you

"What if you lost the key?"

"That's dangerous" His smile turned into an evil grin, he threw away the keys and pulled the chain in your neck