Sea Creatures are the secondary villains of the Frankeweenie (2012) film.
When Bob pours a bag of sea monkey seeds in the pool, he use the electric experiment on the pool and when the lightning strikes the sea monkeys mutate into a small army of mischievous gremlin like monsters and they begin to terrorize the peolpe around town. At the Dutch Day Festival, The Sea Creatures went on a rampage and play tricks on the townspeople.
After witnessing one of the sea creatures eat a box of popcorn and explode after swallowing. Victor and Bob get an idea upon realising that the fresh-water creature can't tollerate salt. The two then make a whole stack of popcorn inside a small tentand the sea creatures went inside to feed on it. Afterward Victor and Bob seal the creatures inside and the tent swells up and explodes into a green slime and the rampage of Sea Creatures is over.