Just read through the thread, surprised nobody's really mentioned Shia LaBeouf or Megan Fox - after Transformers both really went downhill.
For Shia, following the third TF film he appeared in a few other films (Eagle Eye, some film called 'Source Code' which is basically kind of using the rewind-time gimmick of Edge of Tomorrow except it's on a train or something and a lot less exciting from what I remember, and of course Crystal Skull) but he suddenly dropped off the face of the earth for a while...until he showed up in articles about getting arrested for getting drunk and either assulting somebody or just drunk driving I don't recall which. He's kept going downhill ever since, between showing up at some public event wearing a paper bag, then making a big deal about appearing in some porno, but the worst had to be that plagiarized script. Seriously, if you're apologizing for blatant plagerism, you look like a real piece of shit when people learn your apology was also heavily plagiarized! Thankfully after that debacle, the only thing of note he seems to have done since was make some motivational video though for what reasons I have no idea.
As for Megan Fox, generally screaming at your boss on set that he's Hitler is a surefire way to screw up your career. Not like she really had one - she's ok in the first TF film but you can literally see her in the background of some shots rolling her eyes or doing other things entirely out of character, and she's not much of an actress to begin with in the talent department. Then she got plastic reconstruction or something and, I don't know about anybody else, but frankly I think she looks uglier for it. I'm guessing the only two post-TF2 roles I know of she's actually gotten - some prostie in Jonah Hex and as the main possessed chick who screws all her victims in Jennifer's Body, both films being pretty terrible for the record - indicate most people agree as well, since past 2010 I don't know what she's been up to but it probably isn't starring in good films.
