To be totally fair to Ellar Coltrane, he's only acted in a few roles over his brief career to date, but is a special case because his first role took twelve years to film, as protagonist Mason in Richard Linklater's universally-acclaimed Boyhood.
Off the back of Coltrane's fantastic work in the film, it seemed like the future was bright for the young actor...but then he appeared in James Ponsoldt's adaptation of Dave Eggers's acclaimed dystopian novel, giving one of the very worst performances of the year.
Coltrane plays Mercer, one of protagonist Mae's (Emma Watson) pals with a severe dislike for modern technology, especially as in this movie it starts to encroach upon basic human privacy to a troubling extent.
Coltrane doesn't have a huge role, but every time he's on screen his line readings are hilariously bad, and when he finally dies, it comes as a jubilant moment of relief, which is surely not what was intended.
Whether Coltrane's career flourishes or flounders from this point, he's probably, hopefully never going to deliver work this awful ever again.
Which actors do you feel most decisively hit rock bottom in 2017? Shout them out in the comments!