Ok, I may or may not have dreamed this up, but I do remember riding my bike when I was 10 or so and singing the theme to this song, so I think it was real.

Anyway, it was this cartoon (or could have been a movie) from the 80s/90s that had these group of teens (like Scooby except not) who would time travel? or something and there was the bad guy who had a pet dragon who was always goofing things up.

There was a part where the group of teens were running through a flower field (perhaps during the opening/ending scene) but they were as tall as the flowers. Like they shrunk or something.

Thanks!