Gachaman

One day, Kaito Kuji, a high school student, got knocked out and lost all his memories. When he woke up, a gacha machine crank and a sign that says "Thank You" was attached to his chest. He can gain special powers and recollect some of his memories when someone utters those words to him and he turns the crank.

Original Manga: Manga One, Ura Sunday, Ura Shonen Sunday Comics | Mechacomic