Justin Rockcandy is a character that was written and appeared (flashback or theory) in the episode "The Diary."
He was the high school crush of Nurse Betsy Pound Cake and was written all over her diary. In the episode, Justin invited her to a date at Love Tree Point for her birthday, but according to the diary, she was ill and couldn't see Justin before her Birthday. On her birthday, she managed to try and meet him at the point but caught Justin making out with her best friends, Taffi and Mochi. Ever since then, she has hid away from the world and split with Justin.
In the present, Justin is a non-fictional diary story in Adventure Time has never been seen in the series his appearances are all flashbacks and theories, Justin has never officially been seen in Adventure Time, but has only been written in the diary that T.V. found. Justin's current status or existence is unknown.
Justin is a Candy Person who has the body of a an orange/brown rocky structure person. His body is translucent and he wears a blue snapback on his head.
Justin's personality was written in the diary and was never confirmed if not to be believed. He had feelings for Nurse Pound Cake in the past and was desperate to go on a date with her on her birthday. When he talks, he is normally calm, if not, nervous. He used to send Betsy flowers while she was ill meaning that he cared for her. One day, he stopped sending flowers and when Betsy tried to meet him on his birthday, he was caught cheating by making out with her best-friends. Justin's patience must have died out. According to Betsy's letter, Justin was also clingy.