回忆只能亿却不能回c
[huí yì zhĭ néng yì què bù néng huí c]
This nickname means that one can only recall memories ('忆' means 'recall', but it's creatively spelled as '亿', meaning billion) but can't go back to the past. It also contains an English letter 'c' possibly representing some unique feeling towards the irreversible flow of time.