as in the title of the post. I saw it used as "rick rollst" and "gerick rolled" in a Reddit post. Would it be considered a mistake if I used it on a test? And how should I do it? (Screenshot of the Reddit thread: https://media.discordapp.net/attachments/454245855059378176/660992496507027466/Screenshot_20191230-004803.png?width=380&height=676)
Would it be considered a mistake if I used it on a test?
This is impossible to answer. It depends on your teacher. If your teacher is not familiar with it, they will probably mark it as a mistake. And even if you explain this afterwards, they might be not open for internet bullshit. So do it at your own risk.
But how would we write this phenomenon correctly?
Checking the German version of Wikipedia is an obvious start and we find
„You have been Rickrolled“ (dt.: „Du bist gerickrollt worden“)
Starting from the English (to) Rickroll we add -en to make it a German verb. In this process we also let go of the capitalisation, which yields rickrollen. Following common German declination rules, the participle becomes gerickrollt.