The Movie: 'An American Werewolf in London' (1981)
The Scene: David Kessler (David Naughton) is having a boring day: he's recently been released from the hospital (following a strange wolf attack) and he's puttering around the flat of his new lover all aimless and bored. And then, just when the tedium gets sort of suspenseful ... all hairy hell breaks loose. Not only is David about to become a ravenous American werewolf in an unsuspecting London; he's about to show us how outrageously painful this sort of transformation would actually be. (Still, one night with Jenny Agutter might be worth it.)
Why It's Iconic: Aside from it being a simply amazing (and colorfully horrifying) sequence to watch (over and over), the "transformation" is also a special effects benchmark that will never be surpassed. Previous werewolf movies depended on a variety of camera tricks to turn their leading men all lycanthropic, but here director John Landis and FX master Rick Baker are intent on showing you every new hair, every cracked rib, and every strained tendon. For a taste of how this scene would be created today, just take a look at this year's CG-slathered 'Wolfman' remake. (Better yet, don't.)
Imitators/Flatterers: Despite the fact that 1981/'82 saw three different werewolf flicks (the other two were 'Wolfen' and 'The Howling'), it's not that heavily visited of a sub-genre. Putting aside last year's errant remake, most werewolf flicks are either solid indies (like 'Ginger Snaps' or 'Dog Soldiers') or big-budget wolf droppings like 'Cursed'. And I frankly cannot recall how effective the transformations were in 'An American Werewolf in Paris' and you can't make me.
Simply put, nobody imitates this sequence because they'd be nuts to do it.