He is best known for his popular horror thriller anthology webtoon series Tales of the Unusual [ko], which has gained widespread acclaim both Korean and global readers.
The first one, called Author J, ran from October 2009 to November 2010 and tells the story of a deceased writer whose mind has been transferred to a computer AI.
Unlike Seong-dae's previous webtoons, Tales of the Unusual is a horror and thriller genre, containing elements of supernatural, psychological suspense, mystery, satire, black comedy, drama, science fiction, and dark-modern fantasy.
The story follows a middle-aged man who is haunted by ghostly visions of his late dementia-ridden wife after she passes away in a tragic accident.
550,000 people shared the comic just two days after she had posted it, making it an instant hit among the Chinese community, and bringing Seong-dae much fame.
From February 10 to 15, 2015, Seong-dae attended the Taipei International Comics and Animation Festival along with fellow webtoon artist massstar.
The story follows a young woman who uses a cosmetic liquid product to achieve her desired looks, akin to plastic surgery.
As the story touched on contemporary social issues, it was quickly viewed by over 1,000,000 people, making it an instant hit among the Chinese community and raising Seong-dae's profile in China once more.
[9] From October 1 to 5, 2015, Seong-dae attended and gave autographs to his fans with fellow webtoon artists Jo Seok, Son Jae-ho, and Lee Kwang-soo at the China International Comic Festival EXPO.
Each 20 episodes is adapted from 13 short stories, including The Dream-sharing Stone, The Hole, The Chatroom, The Teleporter, A Mysterious Package, The Pet Wig, Jayce's Pen, The Ghost Polaroids, Hair, 14K, Scene Box, Insomnia, and The Mole Stitcher.
After debuting at several international film festivals, it was released on September 9, 2020, in Taiwan, Singapore, Hong Kong, Australia, and New Zealand.
[10] On November 3, 2020, Seong-dae won "Today's Our Manhwa Award" for his webtoon, Tales of the Unusual from the Ministry of Culture, Sports and Tourism.