Classic public domain film, digitally preserved and free to stream forever.
Monster from a Prehistoric Planet (1967), also known as Gappa the Triphibian Monster, follows a Japanese expedition to a tropical island that takes a baby creature back to Tokyo for a theme park — only for its enormous parents to tear across the ocean in a furious rampage to reclaim their offspring.
Starring Tamio Kawachi, Yôko Yamamoto, and Yuji Okada. This film is in the public domain and free to watch, download, and share.