Appears in: The Host (2006)
Scariest moment: The creature's forceful introduction, when the oversized water-dweller leaps out of the Han River and decimates its way through a crowd of shell-shocked humans.
Weakness: Little girls (but not in the perverted way).
In the tradition of Japan's Godzilla, South Korean director Bong Joon-ho's underrated monster movie The Host taps into the fears associated with the military's interferences within the natural order. Here, the amphibious beast that emerges from the Han River is the result of an American pathologist dumping hundreds of bottles of formaldehyde into a sewer system that leads into the Han.
Once it pops up to say "Fuck you" to everyone in sight, The Host's antagonist, dubbed "Gwoemul," barrels through myriad people before kidnapping a cute little girl and solidifying itself as a top player within the big monster pantheon. No hard feelings, Mothra.