9. The Leviathans - Supernatural
For the standards of a CW show, Supernatural boasts relatively solid production values, but there's no escaping how absolutely horrid - and not in the intended way - the Leviathans look.
The man-eating shapeshifters typically reveal their true nature when their human faces transform into a gaping maw of jagged teeth complete with a forked tongue.
It's a terrifying idea in theory, but the VFX are so uniformly cheap that they end up resembling goofy B-movie villains rather than cosmic nightmare fuel.
It's easy to believe that these effects are the result of interns at the effects house being given a Friday afternoon to motion-track a low-fi 3D animation onto an actor's face. Worse still, they all looked terrible even a decade ago when these episodes originally aired.
Any small measure of fear the Leviathans still hold in your heart will surely evaporate if you dare to pause any of their so-called "money shots."