Kids have a toy which turns out to be a dragon egg

It's been a while if I watched the movie so I apologise if I leave key things out or none of it makes sense.

The movie is about kids/teens who are gifted/found a toy/object which turns out to be dragon/creature which is weak against water. I think water made the creature break apart and at the end it didn't die but reverted back to its original form.

Been trying to get a name of this movie, thanks in advance.