Dragon actually comes to be real!

I thought I had remembered and found all the old movies I had forgotten, but today I remember two... going to ask separately for them.

I think it's a Chinese movie, but not 100% sure. Maybe some European. A kid's movie. Some '90s or late '80s.
Not sure what was the point, or main idea, don't remember the story of the movie, but some kids did something like trying to prank citizens with some big rubber dragon. Not sure what was the point, but remember their big rubber dragon, but at the end of the movie comes a real (I think blue) dragon string from the sea!
Sadly can remember anything more or give any more informations!

This sounds like "The Johnstown Monster", from 1971. This was set in Ireland, with an Irish cast.

Hmm... that looks similar, pretty similar or even that's it! BUT!
I can't say anything without seeing a scene of revelation of a monster!

Well, it has a monster revelation scene at the end. It's been a long time since I have seen it. The point is that the "Johnstown Monster" only appears once every hundred years. So the children of Johnstown realize that isn't very good for tourism, the tourists will come if there is a monster seen on a more regular basis. So they fake a monster. At then end of the movie the bad guys expose their fakery, but then the real monster actually rises in the lake,