Mr. — Back

Choi Go-bong, a greedy 70-year-old hotel conglomerate president, magically transforms into a 30-year-old man.

Because of his technical contributions and stylistic similarities in writing, some believe Back could be the pseudonymous Bitcoin creator, though he strongly denies it . 3. Digital Content & Web Series

In the world of Bitcoin, "Mr. Back" refers to , a prominent British cryptographer. Mr. Back

A TikTok and YouTube creator known for short mixes and live DJ sets .

The name is also used for smaller web-based projects and social media personas: Digital Content & Web Series In the world of Bitcoin, "Mr

The most common reference is the 16-episode MBC TV series starring Shin Ha-kyun and Jang Na-ra.

Under his new name, Choi Shin-hyung, he experiences love for the first time with a young part-timer, Eun Ha-soo, and attempts to reconcile with his estranged son. The name is also used for smaller web-based

A breezy romantic fantasy with comedic elements, often highlighting the protagonist's elderly habits in a young body.