Reptilicus (1961)

 Copper miners in the tundras of Lapland discover a frozen 

piece of reptilian tail belonging to some unknown prehistoric 

creature. Taking the specimen to an aquarium in Copenhagen, 

Professor Martens (Asbjorn Andersen) gets more than he 

bargained for when the tail regenerates into a giant, acid 

spitting monster that terrorizes the country. The Danish 

military, led by U.N.-appointed American general Mark Grayson 

(Carl Ottosen) attempts to hunt down the monster and destroy 

it, only to realize that blowing the thing up will create hundreds 

of little creatures. (IMDB Jeremy Lunt) 

Two versions were filmed: One was the original Danish version, and the other was filmed with the actors speaking English. All actors were in both versions, except for actress Bodil Miller, who was unable to speak English. Her character of Connie Miller was played in the English-speaking version by Marlies Behrens. American International Pictures used the English version for the US release, and not only heavily edited it, but dubbed over the Danish actors. 

A novelization of the film was published at the time of the film's release, as was a short-lived comic book series.