An expedition discovers a dinosaur egg on a remote Pacific island inhabited by Japanese people in blackface. Despite their dire warnings the freshly hatched juvenile is returned to Tokyo to be made sport of. Its parents soon arrive AND BEGIN TO DESTROY THE CITY. TANKS AND MISSILES ARE POWERLESS TO STOP THEM.

Also known as "Monster from a Prehistoric Planet", which somehow doesn't sound right. It seems that Gappa is the name of this whole genus of dinosaur rather than of a particular individual. Gappa japonicus is well documented in the fossil record, being one of only a small number of species to evolve anti-gravity and an oral death ray. There's a complete specimen on display at the British Museum of Natural History. I've seen it.

The movie is basic, workmanlike kaiju eiga, remarkable mainly for its delightful American trailer which will make you want to pointlessly yell "GAP-PA!" whenever you think about it. One negative is a small amount of child/baby monster affinity, but it's nothing like the sort of sugary pablum that makes the Gamera movies unwatchable outside of MST3K.

The centrepiece of the film is a long, drawn out sequence of the the clumsy Gappas shuffling through Tokyo wrecking stuff and melting little tanks, complete with those weird screechy monster noises unique to Japanese kaiju. It's strangely soothing to me. I like to queue up about three of these and take a nap when I'm stressed out; I'll half wake every so often and hear the monsters still stomping and carrying on, then drift back to sleep reassured that all is well.

The film is public domain by the way, so feel free to dub it into the language of your own weird country and sell 'em by the millions. Maybe you'll be the next Sandy Frank.

Oh and Gappas are "triphibian". Hope that helps.