For the longest time, I've been seeing this poster for some unknown Thailand film, which appears to have a giant frill-neck lizard lurking the African countryside. The only things that I know for sure about it is that it’s probably from the 1970s and was made by Chiyo Productions.
There is also a slight chance that the film and / or its monster are called ‘Mydoom’ but again, I’m very unsure about this last tidbit.
Here is a small poster or DVD cover for the film. There were bigger poster images available on Chiyo's old official page before that got pulled off due to the whole Ultraman Millennium debacle.

And here is what I believe to be a blurry screen shot from the film, where a Frilled-Neck giant is seen on the left side. But the presence of the Jumborg Ace like superhero with the ‘light saber’ on the right brings some doubt of wither this is the same film. Perhaps I stumbled upon TWO frill-necked lizard monster movies from Thailand?

I hope I get some kind of solid answers to the above mentioned questions, but afraid the Chiyo Productions connection will just bring a bunch of bias Ultraman related chat instead. Or like my thread on the obscure Japanese fantasy/ kaiju film "Diva in the Netherworld" it will be met with complete apathy.
Prove me wrong though and major thanks to the more positive replies and MZ members as well.