Chiteki de Cool na Kouhai Bijo, Ore no Kai Neko ni Naru.

While bedridden with a severe cold, the protagonist's quiet recovery is suddenly interrupted by an extraordinary visitor. A stunning young woman with cat ears materializes by his side, making an unbelievable claim: she is actually his pet cat, somehow transformed into human form. What begins as a feverish hallucination quickly proves to be reality, introducing him to a mysterious beauty who completely upends his ordinary life. The transformation brings about a striking shift in personality. As a feline, she maintained a cool and aloof demeanor, keeping her distance with characteristic independence. However, in her new human guise, that icy exterior melts away entirely. The once-detached cat becomes overwhelmingly affectionate, showering her owner with constant warmth and devotion. This unexpected dynamic blossoms into a tender romance between the bewildered protagonist and his enigmatic companion, blending everyday life with a touch of the supernatural. Originally gaining massive popularity as a video-manga on YouTube, where it captivated audiences and amassed over 2.5 million views, this charming love story has now been officially serialized on the web for readers to enjoy in full.