common messages in science fiction

"Hot Noodles request to add you as a friend." An inexplicable friend request, a non-existent contact. Claiming to be a message from herself in the future, intimately knowledgeable about her past. Fang Xiaocao was utterly numb. Hot Noodles: Danger, do not go home tonight. "Is this some kind of joke?" Staring at the WeChat message, Fang Xiaocao rolled her eyes and opened the anti-theft door. Hot Noodles: At midnight, when the knocking starts, don't turn on the light if you don't want to die. In the early morning: 00:00:00 Fang Xiaocao was woken by the knocking sound. She was just about to turn on the bedside lamp when she remembered that bizarre message. She pulled back her hand and stayed put until dawn, only to know her neighbor next door, a woman living alone just like her was murdered at midnight... Fang Xiaocao was suddenly covered in a cold sweat. Hot Noodles: To celebrate our narrow escape from death, go to the flea market before three in the afternoon, stall number 7, and buy the seventh inkstone on the left-hand side. The seller's bottom price is 80, but the inkstone is worth 8 million. After last night's ordeal, Fang Xiaocao inexplicably chose to believe. She successfully bought an inkstone for a hundred dollars, and later discover it was indeed a imperial inkstone from the Qing Qianlong era, worthing 8 million! Fang Xiaocao stood there, dumbfounded! Following the message's instructions, she bought a second-hand car. But little did she know, the guidance was linking her into a series of events that dragged out a murder case and a fortune worth two small goals. Who on earth sent her the messages? It's really her future self? Or it's some kind of bizarre game?