his is a tricky question, because if a movie is awful enough, it's actually good because it's entertaining in a train-wreck sense of a way.
But the worst movie I ever seen, just off the top of my head
But the worst movie I ever seen, just off the top of my head

My friend put me onto this after he rented it thinking it would b a blade ripoff, what he found was something priceless- the likes of which have never been seen before. The first time watched this was when I was 18 n first really started smoking weed like that, so I would get extra giggly when I was zooted. Needless to say I was high as balls when I popped this In and within the first 5 minutes I had to shut the movie off cuz I was laughing so hard I thought I was gonna pass out. It's that bad, but it's also funny as HELL. I wish I could find a working link online for this but I think the only way to get it is on netflix(not instant watch). They actually had it at blockbuster at the time lol. Anyway I've never seen a movie that even comes remotely close in terms of shear horrible acting, nonsensical plot, abysmal action scenes, and even shyttier dialogue. The funniest part is this movie is the brainchild of its main star, Ron Hall, who wrote directed and starred in this piece of shyt, so you know it's completely serious. Oh yeah and it's got some of the worst special effects I've ever seen in my life. Anyone of us could make a better movie out first go around w no problem n I'm not even joking. If u want to laugh until tears come streaming down your face, watch vampire assassin.
What Is That 
I know they say don't judge a book by it's cover but goddamn! I wouldn't have watched that movie just by looking at the case.

...what a debacle