User blog comment:Titanollante/Daiei's Destroy All Monsters?/@comment-3367060-20150408004030

This is (as far as I can find) the only place where this specific plot is mentioned: http://blogs.yahoo.co.jp/nsrpp579/8665755.html

The thing is that Jiger and Gyaos and Barugon and all these other guys don't seem to be mentioned in the same place as Wyvern in like, any site I can find... Maybe I was searching for the wrong things but until I can find more places mentioning something along this plot (other than 2ch, since that's not even remotely reliable...) then it's not gonna get a page.

This plot is apparently mentioned in the book, "強いぞ！ガメラ"