Koisuru Neko wa Naderaretai

Kotetsu, a black cat, has a crush on Okazaki, a clerk at a pet shop, and he makes a wish to meet Okazaki. Just as he makes his wish, he was transformed into a human before he knew it! With his ears and tails tucked away, Kotetsu spent his days frequenting the pet shop when, suddenly, Okazaki strikes up a conversation with him...?!

(Source: Futabasha, translated)