Not sure which movie this is based on for sure... it's from 1968, so I'd guess it's from Destroy All Monsters!
By the way, if the next bunch of posts seems a bit short on commentary, it's probably because I just discovered, after creating posts through two months from now, that I was repeating items on every single one of them! Sheesh...
CBT: Shazam! A Circus Adventure
3 hours ago